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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Type of ceramic wirewound resistor?
I have one in front of me labelled
UTM 210-9 25435,3 watt probably Russian and can find no info Like the standard pillar white/grey ceramic resistors but instead of the wire returning down the flute of the ceramic there is a sprung join set in the flute with bismuth solder or something. Anyone know a generic name for this type of thermal cut out resistor or a maker name ? Other than the opening temperature must be greater than the sustained power rating temp of the resistor and lower than standard solder, anyone know what sort of safety cut out temperature? |
#2
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Type of ceramic wirewound resistor?
N_Cook Inscribed thus:
I have one in front of me labelled UTM 210-9 25435,3 watt probably Russian and can find no info Like the standard pillar white/grey ceramic resistors but instead of the wire returning down the flute of the ceramic there is a sprung join set in the flute with bismuth solder or something. Anyone know a generic name for this type of thermal cut out resistor or a maker name ? Other than the opening temperature must be greater than the sustained power rating temp of the resistor and lower than standard solder, anyone know what sort of safety cut out temperature? Woods metal is used to secure the spring ! So about 70C. -- Best Regards: Baron. |
#3
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Type of ceramic wirewound resistor?
Baron wrote in message
... N_Cook Inscribed thus: I have one in front of me labelled UTM 210-9 25435,3 watt probably Russian and can find no info Like the standard pillar white/grey ceramic resistors but instead of the wire returning down the flute of the ceramic there is a sprung join set in the flute with bismuth solder or something. Anyone know a generic name for this type of thermal cut out resistor or a maker name ? Other than the opening temperature must be greater than the sustained power rating temp of the resistor and lower than standard solder, anyone know what sort of safety cut out temperature? Woods metal is used to secure the spring ! So about 70C. -- Best Regards: Baron. Must be higher than that, as a rule of thumb or finger I've come across plenty of in service droppers that are too hot to touch more than fleetingly which means 70 C or above. Unfortunately my variable soldering iron cannot go down that low to try this one in front of me. Looks like a lump of metal with thermometer in it, heated on the stove to check this one |
#4
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Type of ceramic wirewound resistor?
N_Cook Inscribed thus:
Baron wrote in message ... N_Cook Inscribed thus: I have one in front of me labelled UTM 210-9 25435,3 watt probably Russian and can find no info Like the standard pillar white/grey ceramic resistors but instead of the wire returning down the flute of the ceramic there is a sprung join set in the flute with bismuth solder or something. Anyone know a generic name for this type of thermal cut out resistor or a maker name ? Other than the opening temperature must be greater than the sustained power rating temp of the resistor and lower than standard solder, anyone know what sort of safety cut out temperature? Woods metal is used to secure the spring ! So about 70C. -- Best Regards: Baron. Must be higher than that, as a rule of thumb or finger I've come across plenty of in service droppers that are too hot to touch more than fleetingly which means 70 C or above. Unfortunately my variable soldering iron cannot go down that low to try this one in front of me. Looks like a lump of metal with thermometer in it, heated on the stove to check this one I've got some resistors with thermal breaks attached kicking about somewhere. If I recall they were used in some TV sets. If I can lay my hands on them I'll have a look and see what values they are. I do recall being warned not to solder them closed, but to replace them with new ones. -- Best Regards: Baron. |
#5
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Type of ceramic wirewound resistor?
Baron wrote in message
... N_Cook Inscribed thus: I have one in front of me labelled UTM 210-9 25435,3 watt probably Russian and can find no info Like the standard pillar white/grey ceramic resistors but instead of the wire returning down the flute of the ceramic there is a sprung join set in the flute with bismuth solder or something. Anyone know a generic name for this type of thermal cut out resistor or a maker name ? Other than the opening temperature must be greater than the sustained power rating temp of the resistor and lower than standard solder, anyone know what sort of safety cut out temperature? Woods metal is used to secure the spring ! So about 70C. -- Best Regards: Baron. 70 degrees C is the standard ambient temp maximum for the specified power rating of a resistor , not its in service maximum temperature. |
#6
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Type of ceramic wirewound resistor?
On Mon, 10 Oct 2011 08:48:23 +0100, "N_Cook"
wrote: I have one in front of me labelled UTM 210-9 25435,3 watt probably Russian and can find no info Like the standard pillar white/grey ceramic resistors but instead of the wire returning down the flute of the ceramic there is a sprung join set in the flute with bismuth solder or something. Anyone know a generic name for this type of thermal cut out resistor or a maker name ? Other than the opening temperature must be greater than the sustained power rating temp of the resistor and lower than standard solder, anyone know what sort of safety cut out temperature? Used to be quite common in TV sets (fusible resistor). Have a look at the top left diagram on page 4 of this which shows mechanical drawing:- http://www.vishay.com/docs/21008/kk.pdf Geo |
#7
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Type of ceramic wirewound resistor?
Geo wrote in message
... On Mon, 10 Oct 2011 08:48:23 +0100, "N_Cook" wrote: I have one in front of me labelled UTM 210-9 25435,3 watt probably Russian and can find no info Like the standard pillar white/grey ceramic resistors but instead of the wire returning down the flute of the ceramic there is a sprung join set in the flute with bismuth solder or something. Anyone know a generic name for this type of thermal cut out resistor or a maker name ? Other than the opening temperature must be greater than the sustained power rating temp of the resistor and lower than standard solder, anyone know what sort of safety cut out temperature? Used to be quite common in TV sets (fusible resistor). Have a look at the top left diagram on page 4 of this which shows mechanical drawing:- http://www.vishay.com/docs/21008/kk.pdf Geo if page 41 and in thermally cutout view , sprung open, then yes that type. I'll have another look tomorrow in that pdf but I could not see the melt temperature. Only approximate this. Some flux over the join of this one in front of me and then using the temp read function of my soldering iron before switching off before reaching set point. Approx 130 deg C no cutout , 160 deg cuts out |
#8
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Type of ceramic wirewound resistor?
Geo Inscribed thus:
On Mon, 10 Oct 2011 08:48:23 +0100, "N_Cook" wrote: I have one in front of me labelled UTM 210-9 25435,3 watt probably Russian and can find no info Like the standard pillar white/grey ceramic resistors but instead of the wire returning down the flute of the ceramic there is a sprung join set in the flute with bismuth solder or something. Anyone know a generic name for this type of thermal cut out resistor or a maker name ? Other than the opening temperature must be greater than the sustained power rating temp of the resistor and lower than standard solder, anyone know what sort of safety cut out temperature? Used to be quite common in TV sets (fusible resistor). Have a look at the top left diagram on page 4 of this which shows mechanical drawing:- http://www.vishay.com/docs/21008/kk.pdf Geo Yes ! Those are the ones I remember. Looking at the power curves suggests that they could get extremely hot, however the top graph suggests 70C. The body temperature could get to be far more than that depending upon how long and how good the heat conduction to that joint is. -- Best Regards: Baron. |
#9
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Type of ceramic wirewound resistor?
Geo wrote in message
... On Mon, 10 Oct 2011 08:48:23 +0100, "N_Cook" wrote: I have one in front of me labelled UTM 210-9 25435,3 watt probably Russian and can find no info Like the standard pillar white/grey ceramic resistors but instead of the wire returning down the flute of the ceramic there is a sprung join set in the flute with bismuth solder or something. Anyone know a generic name for this type of thermal cut out resistor or a maker name ? Other than the opening temperature must be greater than the sustained power rating temp of the resistor and lower than standard solder, anyone know what sort of safety cut out temperature? Used to be quite common in TV sets (fusible resistor). Have a look at the top left diagram on page 4 of this which shows mechanical drawing:- http://www.vishay.com/docs/21008/kk.pdf Geo The KKE Si derating curve maxes out at 150 deg C , so that must be the fusing temp, agrees with this one |
#10
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Type of ceramic wirewound resistor?
"N_Cook" wrote in message ... I have one in front of me labelled UTM 210-9 25435,3 watt probably Russian and can find no info Like the standard pillar white/grey ceramic resistors but instead of the wire returning down the flute of the ceramic there is a sprung join set in the flute with bismuth solder or something. Anyone know a generic name for this type of thermal cut out resistor or a maker name ? Other than the opening temperature must be greater than the sustained power rating temp of the resistor and lower than standard solder, anyone know what sort of safety cut out temperature? Back in the day when I was a TV engineer, they were very common, and known as 'spring-off resistors'. Often used to be used in the feed to the HOP stage, and would spring open when the HOP valve failed. They were usually re-soldered with what we knew just as 'high melting point solder'. I've no idea what actual temperature the stuff was, just that it was issued to us, a few feet at a time, for re-soldering these devices. The Adcola irons that we used (about 50 watts, as I recall ??) struggled a bit with it, but were ultimately capable of making the joint quite nicely. Arfa |
#11
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Type of ceramic wirewound resistor?
Arfa Daily wrote in message
... "N_Cook" wrote in message ... I have one in front of me labelled UTM 210-9 25435,3 watt probably Russian and can find no info Like the standard pillar white/grey ceramic resistors but instead of the wire returning down the flute of the ceramic there is a sprung join set in the flute with bismuth solder or something. Anyone know a generic name for this type of thermal cut out resistor or a maker name ? Other than the opening temperature must be greater than the sustained power rating temp of the resistor and lower than standard solder, anyone know what sort of safety cut out temperature? Back in the day when I was a TV engineer, they were very common, and known as 'spring-off resistors'. Often used to be used in the feed to the HOP stage, and would spring open when the HOP valve failed. They were usually re-soldered with what we knew just as 'high melting point solder'. I've no idea what actual temperature the stuff was, just that it was issued to us, a few feet at a time, for re-soldering these devices. The Adcola irons that we used (about 50 watts, as I recall ??) struggled a bit with it, but were ultimately capable of making the joint quite nicely. Arfa Are you saying it was somehow solder that needed a lot of heat rather than a lot of temperature? |
#12
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Type of ceramic wirewound resistor?
"N_Cook" wrote in message ... Arfa Daily wrote in message ... "N_Cook" wrote in message ... I have one in front of me labelled UTM 210-9 25435,3 watt probably Russian and can find no info Like the standard pillar white/grey ceramic resistors but instead of the wire returning down the flute of the ceramic there is a sprung join set in the flute with bismuth solder or something. Anyone know a generic name for this type of thermal cut out resistor or a maker name ? Other than the opening temperature must be greater than the sustained power rating temp of the resistor and lower than standard solder, anyone know what sort of safety cut out temperature? Back in the day when I was a TV engineer, they were very common, and known as 'spring-off resistors'. Often used to be used in the feed to the HOP stage, and would spring open when the HOP valve failed. They were usually re-soldered with what we knew just as 'high melting point solder'. I've no idea what actual temperature the stuff was, just that it was issued to us, a few feet at a time, for re-soldering these devices. The Adcola irons that we used (about 50 watts, as I recall ??) struggled a bit with it, but were ultimately capable of making the joint quite nicely. Arfa Are you saying it was somehow solder that needed a lot of heat rather than a lot of temperature? Dunno really. No. I think I mean that it needed a lot of temperature. The Adcola, with its solid copper bit, certainly produced enough heat at the tip to handle a small job like resoldering that spring, but it did have a little difficulty taking the solder to a 'full flow' consistency, so probably didn't have quite the temperature required. Remember that this was nearly 40 years ago, when a TV engineer's soldering iron was little more than an electric poker ... The solder was just designated "HMP" for high melting point, and as I recall, was a little greyer looking on the reel than 'standard' solder. Arfa |
#13
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Type of ceramic wirewound resistor?
Arfa Daily wrote in message
... "N_Cook" wrote in message ... Arfa Daily wrote in message ... "N_Cook" wrote in message ... I have one in front of me labelled UTM 210-9 25435,3 watt probably Russian and can find no info Like the standard pillar white/grey ceramic resistors but instead of the wire returning down the flute of the ceramic there is a sprung join set in the flute with bismuth solder or something. Anyone know a generic name for this type of thermal cut out resistor or a maker name ? Other than the opening temperature must be greater than the sustained power rating temp of the resistor and lower than standard solder, anyone know what sort of safety cut out temperature? Back in the day when I was a TV engineer, they were very common, and known as 'spring-off resistors'. Often used to be used in the feed to the HOP stage, and would spring open when the HOP valve failed. They were usually re-soldered with what we knew just as 'high melting point solder'. I've no idea what actual temperature the stuff was, just that it was issued to us, a few feet at a time, for re-soldering these devices. The Adcola irons that we used (about 50 watts, as I recall ??) struggled a bit with it, but were ultimately capable of making the joint quite nicely. Arfa Are you saying it was somehow solder that needed a lot of heat rather than a lot of temperature? Dunno really. No. I think I mean that it needed a lot of temperature. The Adcola, with its solid copper bit, certainly produced enough heat at the tip to handle a small job like resoldering that spring, but it did have a little difficulty taking the solder to a 'full flow' consistency, so probably didn't have quite the temperature required. Remember that this was nearly 40 years ago, when a TV engineer's soldering iron was little more than an electric poker ... The solder was just designated "HMP" for high melting point, and as I recall, was a little greyer looking on the reel than 'standard' solder. Arfa So a more sophisticated version of the aluminium foil and nail for a fuse replacement ? |
#14
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Type of ceramic wirewound resistor?
"N_Cook" wrote in message ... Arfa Daily wrote in message ... "N_Cook" wrote in message ... Arfa Daily wrote in message ... "N_Cook" wrote in message ... I have one in front of me labelled UTM 210-9 25435,3 watt probably Russian and can find no info Like the standard pillar white/grey ceramic resistors but instead of the wire returning down the flute of the ceramic there is a sprung join set in the flute with bismuth solder or something. Anyone know a generic name for this type of thermal cut out resistor or a maker name ? Other than the opening temperature must be greater than the sustained power rating temp of the resistor and lower than standard solder, anyone know what sort of safety cut out temperature? Back in the day when I was a TV engineer, they were very common, and known as 'spring-off resistors'. Often used to be used in the feed to the HOP stage, and would spring open when the HOP valve failed. They were usually re-soldered with what we knew just as 'high melting point solder'. I've no idea what actual temperature the stuff was, just that it was issued to us, a few feet at a time, for re-soldering these devices. The Adcola irons that we used (about 50 watts, as I recall ??) struggled a bit with it, but were ultimately capable of making the joint quite nicely. Arfa Are you saying it was somehow solder that needed a lot of heat rather than a lot of temperature? Dunno really. No. I think I mean that it needed a lot of temperature. The Adcola, with its solid copper bit, certainly produced enough heat at the tip to handle a small job like resoldering that spring, but it did have a little difficulty taking the solder to a 'full flow' consistency, so probably didn't have quite the temperature required. Remember that this was nearly 40 years ago, when a TV engineer's soldering iron was little more than an electric poker ... The solder was just designated "HMP" for high melting point, and as I recall, was a little greyer looking on the reel than 'standard' solder. Arfa So a more sophisticated version of the aluminium foil and nail for a fuse replacement ? No, I would say not. I worked for Rediffusion, and they were one of the best 'technical' rental companies in the business. Their training and attention to detail, was second to none, and they used these resistors in their own TV set designs, so if that's what they said was the right way to handle remaking one of these devices after it had sprung off, then you can be pretty sure that it was right. There was never any question of the resistor having to be replaced because it had sprung open ... Arfa |
#15
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Type of ceramic wirewound resistor?
Arfa Daily wrote in message
... "N_Cook" wrote in message ... Arfa Daily wrote in message ... "N_Cook" wrote in message ... Arfa Daily wrote in message ... "N_Cook" wrote in message ... I have one in front of me labelled UTM 210-9 25435,3 watt probably Russian and can find no info Like the standard pillar white/grey ceramic resistors but instead of the wire returning down the flute of the ceramic there is a sprung join set in the flute with bismuth solder or something. Anyone know a generic name for this type of thermal cut out resistor or a maker name ? Other than the opening temperature must be greater than the sustained power rating temp of the resistor and lower than standard solder, anyone know what sort of safety cut out temperature? Back in the day when I was a TV engineer, they were very common, and known as 'spring-off resistors'. Often used to be used in the feed to the HOP stage, and would spring open when the HOP valve failed. They were usually re-soldered with what we knew just as 'high melting point solder'. I've no idea what actual temperature the stuff was, just that it was issued to us, a few feet at a time, for re-soldering these devices. The Adcola irons that we used (about 50 watts, as I recall ??) struggled a bit with it, but were ultimately capable of making the joint quite nicely. Arfa Are you saying it was somehow solder that needed a lot of heat rather than a lot of temperature? Dunno really. No. I think I mean that it needed a lot of temperature. The Adcola, with its solid copper bit, certainly produced enough heat at the tip to handle a small job like resoldering that spring, but it did have a little difficulty taking the solder to a 'full flow' consistency, so probably didn't have quite the temperature required. Remember that this was nearly 40 years ago, when a TV engineer's soldering iron was little more than an electric poker ... The solder was just designated "HMP" for high melting point, and as I recall, was a little greyer looking on the reel than 'standard' solder. Arfa So a more sophisticated version of the aluminium foil and nail for a fuse replacement ? No, I would say not. I worked for Rediffusion, and they were one of the best 'technical' rental companies in the business. Their training and attention to detail, was second to none, and they used these resistors in their own TV set designs, so if that's what they said was the right way to handle remaking one of these devices after it had sprung off, then you can be pretty sure that it was right. There was never any question of the resistor having to be replaced because it had sprung open ... Arfa I must be missing something here , what is the point of the spring off disconnect? |
#16
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Type of ceramic wirewound resistor?
N_Cook Inscribed thus:
Arfa Daily wrote in message ... "N_Cook" wrote in message ... Arfa Daily wrote in message ... "N_Cook" wrote in message ... Arfa Daily wrote in message ... "N_Cook" wrote in message ... I have one in front of me labelled UTM 210-9 25435,3 watt probably Russian and can find no info Like the standard pillar white/grey ceramic resistors but instead of the wire returning down the flute of the ceramic there is a sprung join set in the flute with bismuth solder or something. Anyone know a generic name for this type of thermal cut out resistor or a maker name ? Other than the opening temperature must be greater than the sustained power rating temp of the resistor and lower than standard solder, anyone know what sort of safety cut out temperature? Back in the day when I was a TV engineer, they were very common, and known as 'spring-off resistors'. Often used to be used in the feed to the HOP stage, and would spring open when the HOP valve failed. They were usually re-soldered with what we knew just as 'high melting point solder'. I've no idea what actual temperature the stuff was, just that it was issued to us, a few feet at a time, for re-soldering these devices. The Adcola irons that we used (about 50 watts, as I recall ??) struggled a bit with it, but were ultimately capable of making the joint quite nicely. Arfa Are you saying it was somehow solder that needed a lot of heat rather than a lot of temperature? Dunno really. No. I think I mean that it needed a lot of temperature. The Adcola, with its solid copper bit, certainly produced enough heat at the tip to handle a small job like resoldering that spring, but it did have a little difficulty taking the solder to a 'full flow' consistency, so probably didn't have quite the temperature required. Remember that this was nearly 40 years ago, when a TV engineer's soldering iron was little more than an electric poker ... The solder was just designated "HMP" for high melting point, and as I recall, was a little greyer looking on the reel than 'standard' solder. Arfa So a more sophisticated version of the aluminium foil and nail for a fuse replacement ? No, I would say not. I worked for Rediffusion, and they were one of the best 'technical' rental companies in the business. Their training and attention to detail, was second to none, and they used these resistors in their own TV set designs, so if that's what they said was the right way to handle remaking one of these devices after it had sprung off, then you can be pretty sure that it was right. There was never any question of the resistor having to be replaced because it had sprung open ... Arfa I must be missing something here , what is the point of the spring off disconnect? Its a circuit protection device... -- Best Regards: Baron. |
#17
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Type of ceramic wirewound resistor?
"N_Cook" wrote in message ... Arfa Daily wrote in message ... "N_Cook" wrote in message ... Arfa Daily wrote in message ... "N_Cook" wrote in message ... Arfa Daily wrote in message ... "N_Cook" wrote in message ... I have one in front of me labelled UTM 210-9 25435,3 watt probably Russian and can find no info Like the standard pillar white/grey ceramic resistors but instead of the wire returning down the flute of the ceramic there is a sprung join set in the flute with bismuth solder or something. Anyone know a generic name for this type of thermal cut out resistor or a maker name ? Other than the opening temperature must be greater than the sustained power rating temp of the resistor and lower than standard solder, anyone know what sort of safety cut out temperature? Back in the day when I was a TV engineer, they were very common, and known as 'spring-off resistors'. Often used to be used in the feed to the HOP stage, and would spring open when the HOP valve failed. They were usually re-soldered with what we knew just as 'high melting point solder'. I've no idea what actual temperature the stuff was, just that it was issued to us, a few feet at a time, for re-soldering these devices. The Adcola irons that we used (about 50 watts, as I recall ??) struggled a bit with it, but were ultimately capable of making the joint quite nicely. Arfa Are you saying it was somehow solder that needed a lot of heat rather than a lot of temperature? Dunno really. No. I think I mean that it needed a lot of temperature. The Adcola, with its solid copper bit, certainly produced enough heat at the tip to handle a small job like resoldering that spring, but it did have a little difficulty taking the solder to a 'full flow' consistency, so probably didn't have quite the temperature required. Remember that this was nearly 40 years ago, when a TV engineer's soldering iron was little more than an electric poker ... The solder was just designated "HMP" for high melting point, and as I recall, was a little greyer looking on the reel than 'standard' solder. Arfa So a more sophisticated version of the aluminium foil and nail for a fuse replacement ? No, I would say not. I worked for Rediffusion, and they were one of the best 'technical' rental companies in the business. Their training and attention to detail, was second to none, and they used these resistors in their own TV set designs, so if that's what they said was the right way to handle remaking one of these devices after it had sprung off, then you can be pretty sure that it was right. There was never any question of the resistor having to be replaced because it had sprung open ... Arfa I must be missing something here , what is the point of the spring off disconnect? It opens the resistor, and removes power from the overload condition that it's there to protect against ... Arfa |
#18
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Type of ceramic wirewound resistor?
Arfa Daily wrote in message
... "N_Cook" wrote in message ... Arfa Daily wrote in message ... "N_Cook" wrote in message ... Arfa Daily wrote in message ... "N_Cook" wrote in message ... Arfa Daily wrote in message ... "N_Cook" wrote in message ... I have one in front of me labelled UTM 210-9 25435,3 watt probably Russian and can find no info Like the standard pillar white/grey ceramic resistors but instead of the wire returning down the flute of the ceramic there is a sprung join set in the flute with bismuth solder or something. Anyone know a generic name for this type of thermal cut out resistor or a maker name ? Other than the opening temperature must be greater than the sustained power rating temp of the resistor and lower than standard solder, anyone know what sort of safety cut out temperature? Back in the day when I was a TV engineer, they were very common, and known as 'spring-off resistors'. Often used to be used in the feed to the HOP stage, and would spring open when the HOP valve failed. They were usually re-soldered with what we knew just as 'high melting point solder'. I've no idea what actual temperature the stuff was, just that it was issued to us, a few feet at a time, for re-soldering these devices. The Adcola irons that we used (about 50 watts, as I recall ??) struggled a bit with it, but were ultimately capable of making the joint quite nicely. Arfa Are you saying it was somehow solder that needed a lot of heat rather than a lot of temperature? Dunno really. No. I think I mean that it needed a lot of temperature. The Adcola, with its solid copper bit, certainly produced enough heat at the tip to handle a small job like resoldering that spring, but it did have a little difficulty taking the solder to a 'full flow' consistency, so probably didn't have quite the temperature required. Remember that this was nearly 40 years ago, when a TV engineer's soldering iron was little more than an electric poker ... The solder was just designated "HMP" for high melting point, and as I recall, was a little greyer looking on the reel than 'standard' solder. Arfa So a more sophisticated version of the aluminium foil and nail for a fuse replacement ? No, I would say not. I worked for Rediffusion, and they were one of the best 'technical' rental companies in the business. Their training and attention to detail, was second to none, and they used these resistors in their own TV set designs, so if that's what they said was the right way to handle remaking one of these devices after it had sprung off, then you can be pretty sure that it was right. There was never any question of the resistor having to be replaced because it had sprung open ... Arfa I must be missing something here , what is the point of the spring off disconnect? It opens the resistor, and removes power from the overload condition that it's there to protect against ... Arfa But not if you "weld" it shut with high melting point solder |
#19
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Type of ceramic wirewound resistor?
snip I must be missing something here , what is the point of the spring off disconnect? It opens the resistor, and removes power from the overload condition that it's there to protect against ... Arfa But not if you "weld" it shut with high melting point solder What are you saying exactly ? That 'high melting point' solder was not what was originally used to hold it shut by the manufacturers ? Are you suggesting that a company the size of Rediffusion, who designed their own TV sets making use of these devices, then went on to encourage their (extremely well trained and well thought of in the trade) engineers, to execute some kind of bodge repair on ones that had opened ? No, of course they didn't. If that material is what central stores supplied to the branches for remaking the spring connection, then I think you can be pretty sure that it was appropriate for the job. Presumably, as you found it necessary to ask what one of these resistors was in the first place, you have no experience of them, contemporary with the time that they were commonly in use ? Arfa |
#20
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Type of ceramic wirewound resistor?
On Oct 13, 5:58*pm, "Arfa Daily" wrote:
snip I must be missing something here , what is the point of the spring off disconnect? It opens the resistor, and removes power from the overload condition that it's there to protect against ... Arfa But not if you "weld" it shut with high melting point solder What are you saying exactly ? That 'high melting point' solder was not what was originally used to hold it shut by the manufacturers ? Are you suggesting that a company the size of Rediffusion, who designed their own TV sets making use of these devices, then went on to encourage their (extremely well trained and well thought of in the trade) engineers, to execute some kind of bodge repair on ones that had opened ? No, of course they didn't. If that material is what central stores supplied to the branches for remaking the spring connection, then I think you can be pretty sure that it was appropriate for the job. Presumably, as you found it necessary to ask what one of these resistors was in the first place, you have no experience of them, contemporary with the time that they were commonly in use ? Arfa - Hide quoted text - - Show quoted text - Perhaps N-Cook was thinking of the similar over temperature cutouts used to protect transformers such as used in Philips Tape recorders that used a very low temperature 'solder' to hold the spring connection together. This type of 'fusable link' has been used for well over 100 years and uses very carefully formulated alloy as the sensor to operate at remarkably precise temperatures. The fire sprinkler head is one of the earliest mass produced applications of this technique. Neil S. |
#21
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Type of ceramic wirewound resistor?
"nesesu" wrote in message ... On Oct 13, 5:58 pm, "Arfa Daily" wrote: snip I must be missing something here , what is the point of the spring off disconnect? It opens the resistor, and removes power from the overload condition that it's there to protect against ... Arfa But not if you "weld" it shut with high melting point solder What are you saying exactly ? That 'high melting point' solder was not what was originally used to hold it shut by the manufacturers ? Are you suggesting that a company the size of Rediffusion, who designed their own TV sets making use of these devices, then went on to encourage their (extremely well trained and well thought of in the trade) engineers, to execute some kind of bodge repair on ones that had opened ? No, of course they didn't. If that material is what central stores supplied to the branches for remaking the spring connection, then I think you can be pretty sure that it was appropriate for the job. Presumably, as you found it necessary to ask what one of these resistors was in the first place, you have no experience of them, contemporary with the time that they were commonly in use ? Arfa - Hide quoted text - - Show quoted text - Perhaps N-Cook was thinking of the similar over temperature cutouts used to protect transformers such as used in Philips Tape recorders that used a very low temperature 'solder' to hold the spring connection together. This type of 'fusable link' has been used for well over 100 years and uses very carefully formulated alloy as the sensor to operate at remarkably precise temperatures. The fire sprinkler head is one of the earliest mass produced applications of this technique. Neil S. Yes, agreed, but Mr Cook is very well aware of those, and the standard advice of not to try to repair them for precisely the reason that it is a very low melting point alloy that is originally used. However, the spring-off resistors were designed to be resettable by resoldering. The principle is not quite the same as the transformer thermal fuses, as with the case of the spring-offs, the resistor element is designed to get hot, and conduct the heat into the joint, via the thin wide conductor that is closely fixed to the resistor's ceramic body Arfa |
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Type of ceramic wirewound resistor?
nesesu wrote in message
... On Oct 13, 5:58 pm, "Arfa Daily" wrote: snip I must be missing something here , what is the point of the spring off disconnect? It opens the resistor, and removes power from the overload condition that it's there to protect against ... Arfa But not if you "weld" it shut with high melting point solder What are you saying exactly ? That 'high melting point' solder was not what was originally used to hold it shut by the manufacturers ? Are you suggesting that a company the size of Rediffusion, who designed their own TV sets making use of these devices, then went on to encourage their (extremely well trained and well thought of in the trade) engineers, to execute some kind of bodge repair on ones that had opened ? No, of course they didn't. If that material is what central stores supplied to the branches for remaking the spring connection, then I think you can be pretty sure that it was appropriate for the job. Presumably, as you found it necessary to ask what one of these resistors was in the first place, you have no experience of them, contemporary with the time that they were commonly in use ? Arfa - Hide quoted text - - Show quoted text - Perhaps N-Cook was thinking of the similar over temperature cutouts used to protect transformers such as used in Philips Tape recorders that used a very low temperature 'solder' to hold the spring connection together. This type of 'fusable link' has been used for well over 100 years and uses very carefully formulated alloy as the sensor to operate at remarkably precise temperatures. The fire sprinkler head is one of the earliest mass produced applications of this technique. Neil S. +++++ Someone upthread mentiond a currently available type of them http://www.vishay.com/docs/21008/kk.pdf page 41 top left has a spring open view of the sprung type and top right of p42 has the derating plot showing the maximum operating temperature of 150 degrees for the spring type , compared to 350 degrees for the non-safety, plain vanilla ones |
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