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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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Is recession good for commercial electronic repair ?
Discuss
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#2
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Is recession good for commercial electronic repair ?
Not in its current state, when the cost of repairing an item is comparable
to the cost of a new one. |
#3
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Is recession good for commercial electronic repair ?
"N_Cook" wrote in message ... Discuss I assume you meant commercial repair of consumer goods. If so, my feeling is Yes, but to a limited degree. I doubt that repair shops will see much more than a 5% increase in actual volume (those customers who opt to actually have it repaired). There will be more inquiries. The low-end stuff will remain in the throw-away category and the high-end stuff is mostly already covered by extended warranties (which most consumers opt for). |
#4
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Is recession good for commercial electronic repair ?
Charles wrote in message
. .. "N_Cook" wrote in message ... Discuss I assume you meant commercial repair of consumer goods. If so, my feeling is Yes, but to a limited degree. I doubt that repair shops will see much more than a 5% increase in actual volume (those customers who opt to actually have it repaired). There will be more inquiries. The low-end stuff will remain in the throw-away category and the high-end stuff is mostly already covered by extended warranties (which most consumers opt for). There is a price breakpoint , that varies from owner to owner (company or individual). Cost to repair versus cost to replace, so a ratio. I would assume that breakpoint ratio moves towards favouring repair in resession. Also assuming some degree of essentiality that would also vary with degree of resession. -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ |
#5
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Is recession good for commercial electronic repair ?
"N_Cook" wrote in message ... Charles wrote in message . .. "N_Cook" wrote in message ... Discuss I assume you meant commercial repair of consumer goods. If so, my feeling is Yes, but to a limited degree. I doubt that repair shops will see much more than a 5% increase in actual volume (those customers who opt to actually have it repaired). There will be more inquiries. The low-end stuff will remain in the throw-away category and the high-end stuff is mostly already covered by extended warranties (which most consumers opt for). There is a price breakpoint , that varies from owner to owner (company or individual). Cost to repair versus cost to replace, so a ratio. I would assume that breakpoint ratio moves towards favouring repair in resession. Also assuming some degree of essentiality that would also vary with degree of resession. So you might think, but in my experience, particularly with companies, there are many factors other than price, which drive the decision making process. For instance, one place that I was until a few months ago, repairing large volumes of a particular board for, has been taken over by another company. I was charging them 30 quid a pop to repair them. They are currently buying in new boards from the manufacturer, at 150 quid a time, and throwing the faulty ones away ! (I know this for a fact, as I know someone that works for them). The best of it is that as a part of the repair, I used to carry out a reliability mod, that made them virtually indestructible after it had been carried out. So here we are hovering on the edge of recession, and you would think that a saving of 120 quid a board, and a reduction in your field service call-back rate, would be just what the doctor ordered, but no. For reasons best known to themselves, they throw money away. So how do you reconcile that one ? Just as an aside. I know how much you love valves ... Today, I had a Marshall on the bench. Pair of EL34s in the output. On the tester, it sounded awful, and the 'scope showed a highly assymetric output waveform. The drive to both outputs was fine, and the bias was correct on both valves. The waveforms on the anode of each valve looked pretty similar, but on the back side of the output tranny, it looked lousy. Both valves had screen voltage, fed via a 1k resistor each, but I noticed that the screen volts at the actual pin was 4 volts lower on one valve, than the other. When I measured actually across each screenfeed R, one of them had 4.4 volts across it, and the other had nothing. Turned out that the screen grid was open circuit on that valve. I hung a test one in there, and the voltage drop reappeared as it should, and the waveform on the output was now perfect. A new pair of valves and a bias check finished the job off. How unusual a problem is that ? In all my years of working with valves, I don't think that I can remember ever having had an open circuit screen grid. Arfa |
#6
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Is recession good for commercial electronic repair ?
On 4/16/08 11:02 AM, in article ,
"Arfa Daily" wrote: "N_Cook" wrote in message ... Charles wrote in message . .. "N_Cook" wrote in message ... Discuss I assume you meant commercial repair of consumer goods. If so, my feeling is Yes, but to a limited degree. I doubt that repair shops will see much more than a 5% increase in actual volume (those customers who opt to actually have it repaired). There will be more inquiries. The low-end stuff will remain in the throw-away category and the high-end stuff is mostly already covered by extended warranties (which most consumers opt for). There is a price breakpoint , that varies from owner to owner (company or individual). Cost to repair versus cost to replace, so a ratio. I would assume that breakpoint ratio moves towards favouring repair in resession. Also assuming some degree of essentiality that would also vary with degree of resession. So you might think, but in my experience, particularly with companies, there are many factors other than price, which drive the decision making process. For instance, one place that I was until a few months ago, repairing large volumes of a particular board for, has been taken over by another company. I was charging them 30 quid a pop to repair them. They are currently buying in new boards from the manufacturer, at 150 quid a time, and throwing the faulty ones away ! (I know this for a fact, as I know someone that works for them). The best of it is that as a part of the repair, I used to carry out a reliability mod, that made them virtually indestructible after it had been carried out. So here we are hovering on the edge of recession, and you would think that a saving of 120 quid a board, and a reduction in your field service call-back rate, would be just what the doctor ordered, but no. For reasons best known to themselves, they throw money away. So how do you reconcile that one ? Probably by looking at the real costs of you doing a repair job versus the cost of having a non-technical person simply exchange boards. Also, the new board would have a sizeable markup. Some companies just don't consider what is fair and reasonable, wanting only to maximize profits at the customer and employee's expense. Just as an aside. I know how much you love valves ... Today, I had a Marshall on the bench. Pair of EL34s in the output. On the tester, it sounded awful, and the 'scope showed a highly assymetric output waveform. The drive to both outputs was fine, and the bias was correct on both valves. The waveforms on the anode of each valve looked pretty similar, but on the back side of the output tranny, it looked lousy. Both valves had screen voltage, fed via a 1k resistor each, but I noticed that the screen volts at the actual pin was 4 volts lower on one valve, than the other. When I measured actually across each screenfeed R, one of them had 4.4 volts across it, and the other had nothing. Turned out that the screen grid was open circuit on that valve. I hung a test one in there, and the voltage drop reappeared as it should, and the waveform on the output was now perfect. A new pair of valves and a bias check finished the job off. How unusual a problem is that ? In all my years of working with valves, I don't think that I can remember ever having had an open circuit screen grid. Arfa |
#7
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Is recession good for commercial electronic repair ?
On Apr 15, 1:31 pm, "N_Cook" wrote:
Discuss http://www.youtube.com/watch?v=ap0-SCwi89U ;-) regards, B- |
#8
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Is recession good for commercial electronic repair ?
"Don Bowey" wrote in message ... On 4/16/08 11:02 AM, in article , "Arfa Daily" wrote: "N_Cook" wrote in message ... Charles wrote in message . .. "N_Cook" wrote in message ... Discuss I assume you meant commercial repair of consumer goods. If so, my feeling is Yes, but to a limited degree. I doubt that repair shops will see much more than a 5% increase in actual volume (those customers who opt to actually have it repaired). There will be more inquiries. The low-end stuff will remain in the throw-away category and the high-end stuff is mostly already covered by extended warranties (which most consumers opt for). There is a price breakpoint , that varies from owner to owner (company or individual). Cost to repair versus cost to replace, so a ratio. I would assume that breakpoint ratio moves towards favouring repair in resession. Also assuming some degree of essentiality that would also vary with degree of resession. So you might think, but in my experience, particularly with companies, there are many factors other than price, which drive the decision making process. For instance, one place that I was until a few months ago, repairing large volumes of a particular board for, has been taken over by another company. I was charging them 30 quid a pop to repair them. They are currently buying in new boards from the manufacturer, at 150 quid a time, and throwing the faulty ones away ! (I know this for a fact, as I know someone that works for them). The best of it is that as a part of the repair, I used to carry out a reliability mod, that made them virtually indestructible after it had been carried out. So here we are hovering on the edge of recession, and you would think that a saving of 120 quid a board, and a reduction in your field service call-back rate, would be just what the doctor ordered, but no. For reasons best known to themselves, they throw money away. So how do you reconcile that one ? Probably by looking at the real costs of you doing a repair job versus the cost of having a non-technical person simply exchange boards. Also, the new board would have a sizeable markup. Some companies just don't consider what is fair and reasonable, wanting only to maximize profits at the customer and employee's expense. Perhaps I'm a bit thick tonight Don, but I'm not quite following the logic of that one ! The 'real' cost of me doing a repair to one of their boards is 30 quid. Their field engineers replace boards at the customer site from their van stock. The machines that these boards go in are supplied to the end user F.O.C. , the money being made on supplied product for use in that machine. So there is no repair cost to the customer. The field engineer returns the faulty board to stores, and a spotty faced youth collects them up until he has a batch, and then sends them to me. I duly repair them, and relieve them of 30 quid per board. Fixed price. No hidden charges. 30 quid. That's it. Now, instead of the SFY batching them up and sending them to me, he is batching them up, and flinging them in the dumpster. In the meantime, they are buying in new boards from the company that make the machines, and paying 150 quid each for them. No discounts. No cost percentage recovered from the end user. No offset at all. So that's 150 quid per board, per field repair that uses one, sitting on their books, as opposed to 30 quid per board per field repair if they use me to repair them. That's 120 quid of 'real' cost coming out of their pockets. So explain to me again how that is a better deal for them ... :-) Arfa |
#9
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Is recession good for commercial electronic repair ?
"Arfa Daily" wrote in news:ShxNj.4786$DQ3.3407
@newsfe1-win.ntli.net: So explain to me again how that is a better deal for them ... When I had my repair shop I found that 'if the repair cost less than 1/3 the cost of a new unit, they usually fixed it'. On the other hand, if they could buy a new one for less than 3 times the repair cost, I was going to end up owning a repaired set, even if they said 'go ahead and fix it'. I doubt that people have changed much since I closed my shop. Note: often to 'estimate' the costs of the repair, it was necessary to fix the danged set, and then 'unfix it' if they declined the repair but wanted to pick up the broken set. That was ONE of several reasons I closed my shop in the early 70's. -- bz 73 de N5BZ k please pardon my infinite ignorance, the set-of-things-I-do-not-know is an infinite set. remove ch100-5 to avoid spam trap |
#10
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Is recession good for commercial electronic repair ?
bz wrote in message
98.139... "Arfa Daily" wrote in news:ShxNj.4786$DQ3.3407 @newsfe1-win.ntli.net: So explain to me again how that is a better deal for them ... When I had my repair shop I found that 'if the repair cost less than 1/3 the cost of a new unit, they usually fixed it'. On the other hand, if they could buy a new one for less than 3 times the repair cost, I was going to end up owning a repaired set, even if they said 'go ahead and fix it'. I doubt that people have changed much since I closed my shop. Note: often to 'estimate' the costs of the repair, it was necessary to fix the danged set, and then 'unfix it' if they declined the repair but wanted to pick up the broken set. That was ONE of several reasons I closed my shop in the early 70's. -- bz 73 de N5BZ k please pardon my infinite ignorance, the set-of-things-I-do-not-know is an infinite set. remove ch100-5 to avoid spam trap For newcomers I always charge an upfront "exploration fee" of 8GBP/15USD to 15GBP/30USD, mainly dependent on size, and get back to them by phone or email with some sort of quote for repair, if its a diagnostic repair rather than replacing a mains switch type repair. I can never give a quote , unseen, inside the kit. It avoids total timewasters and gives them a chance to drop out at an earkly stage, but I've not wasted the time of getting inside, etc. -- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on http://home.graffiti.net/diverse:graffiti.net/ |
#11
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Is recession good for commercial electronic repair ?
"N_Cook" wrote in
: ..... For newcomers I always charge an upfront "exploration fee" of 8GBP/15USD to 15GBP/30USD, mainly dependent on size, and get back to them by phone or email with some sort of quote for repair, if its a diagnostic repair rather than replacing a mains switch type repair. I can never give a quote , unseen, inside the kit. It avoids total timewasters and gives them a chance to drop out at an earkly stage, but I've not wasted the time of getting inside, etc. Yep. We always charged $25 checkout fee, UP FRONT, to look at the set. That was applied to the repairs, if they decided to repair the set. -- bz 73 de N5BZ k please pardon my infinite ignorance, the set-of-things-I-do-not-know is an infinite set. remove ch100-5 to avoid spam trap |
#12
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Is recession good for commercial electronic repair ?
N_Cook wrote:
For newcomers I always charge an upfront "exploration fee" of 8GBP/15USD to 15GBP/30USD, mainly dependent on size, and get back to them by phone or email with some sort of quote for repair, if its a diagnostic repair rather than replacing a mains switch type repair. I can never give a quote , unseen, inside the kit. Didn't ASDA have DVD players around Christmas for 10 quid? At that price, you are not going to see many in for an 8 quid estimate. With prices like that, people are just going to buy a cheap new one instead of paying you to fix their old one, no matter how much better it was. Geoff. -- Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM |
#13
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Is recession good for commercial electronic repair ?
On Apr 16, 2:02*pm, "Arfa Daily" wrote:
Just as an aside. I know how much you love valves ... *Today, I had a Marshall on the bench. Pair of EL34s in the output. On the tester, it sounded awful, and the 'scope showed a highly assymetric output waveform. The drive to both outputs was fine, and the bias was correct on both valves. The waveforms on the anode of each valve looked pretty similar, but on the back side of the output tranny, it looked lousy. Both valves had screen voltage, fed via a 1k resistor each, but I noticed that the screen volts at the actual pin was 4 volts lower on one valve, than the other. When I measured actually across each screenfeed R, one of them had 4.4 volts across it, and the other had nothing. Turned out that the screen grid was open circuit on that valve. I hung a test one in there, and the voltage drop reappeared as it should, and the waveform on the output was now perfect. A new pair of valves and a bias check finished the job off. How unusual a problem is that ? In all my years of working with valves, I don't think that I can remember ever having had an open circuit screen grid. Arfa Screen failures are more common with the newer production tubes/ valves. Its either mechanical stress or over dissapation that kills 'em. |
#14
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Is recession good for commercial electronic repair ?
"boardjunkie" wrote in message ... On Apr 16, 2:02 pm, "Arfa Daily" wrote: Just as an aside. I know how much you love valves ... Today, I had a Marshall on the bench. Pair of EL34s in the output. On the tester, it sounded awful, and the 'scope showed a highly assymetric output waveform. The drive to both outputs was fine, and the bias was correct on both valves. The waveforms on the anode of each valve looked pretty similar, but on the back side of the output tranny, it looked lousy. Both valves had screen voltage, fed via a 1k resistor each, but I noticed that the screen volts at the actual pin was 4 volts lower on one valve, than the other. When I measured actually across each screenfeed R, one of them had 4.4 volts across it, and the other had nothing. Turned out that the screen grid was open circuit on that valve. I hung a test one in there, and the voltage drop reappeared as it should, and the waveform on the output was now perfect. A new pair of valves and a bias check finished the job off. How unusual a problem is that ? In all my years of working with valves, I don't think that I can remember ever having had an open circuit screen grid. Arfa Screen failures are more common with the newer production tubes/ valves. Its either mechanical stress or over dissapation that kills 'em. It was a fairly 'new' tube as in 8 years or so, but an original Marshall factory fit. As far as you could see looking through the glass, it was a 'genuine' EL34 pentode, rather than a 6L6 look-alike beam tetrode masquerading as an EL34. The screen grid connection ribbon looked intact. Just for sport, I tried measuring the capacitance from the screen grid to the anode, and it measured exactly the same as on the opposite tube which was working, so that would indicate that the screen was in fact intact. Never-the-less, the bad tube drew no discernible screen current at all. The emission was pretty poor on both tubes, so about the only other thing that I can come up with is that the emission was so low on that tube, that the standing bias had it basically cut off, so the screen had no source of current to draw from. Arfa |
#15
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Is recession good for commercial electronic repair ?
On Wed, 16 Apr 2008 18:02:12 GMT, "Arfa Daily"
put finger to keyboard and composed: So you might think, but in my experience, particularly with companies, there are many factors other than price, which drive the decision making process. For instance, one place that I was until a few months ago, repairing large volumes of a particular board for, has been taken over by another company. I was charging them 30 quid a pop to repair them. They are currently buying in new boards from the manufacturer, at 150 quid a time, and throwing the faulty ones away ! (I know this for a fact, as I know someone that works for them). The best of it is that as a part of the repair, I used to carry out a reliability mod, that made them virtually indestructible after it had been carried out. So here we are hovering on the edge of recession, and you would think that a saving of 120 quid a board, and a reduction in your field service call-back rate, would be just what the doctor ordered, but no. For reasons best known to themselves, they throw money away. So how do you reconcile that one ? I often had the reverse experience. Many large companies with convoluted accounting practices would find it easier to repair something by replacing a board costing $200 instead of requisitioning an entire new unit costing, say, $100. - Franc Zabkar -- Please remove one 'i' from my address when replying by email. |
#16
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Is recession good for commercial electronic repair ?
"Franc Zabkar" wrote in message ... On Wed, 16 Apr 2008 18:02:12 GMT, "Arfa Daily" put finger to keyboard and composed: So you might think, but in my experience, particularly with companies, there are many factors other than price, which drive the decision making process. For instance, one place that I was until a few months ago, repairing large volumes of a particular board for, has been taken over by another company. I was charging them 30 quid a pop to repair them. They are currently buying in new boards from the manufacturer, at 150 quid a time, and throwing the faulty ones away ! (I know this for a fact, as I know someone that works for them). The best of it is that as a part of the repair, I used to carry out a reliability mod, that made them virtually indestructible after it had been carried out. So here we are hovering on the edge of recession, and you would think that a saving of 120 quid a board, and a reduction in your field service call-back rate, would be just what the doctor ordered, but no. For reasons best known to themselves, they throw money away. So how do you reconcile that one ? I often had the reverse experience. Many large companies with convoluted accounting practices would find it easier to repair something by replacing a board costing $200 instead of requisitioning an entire new unit costing, say, $100. - Franc Zabkar Yes Franc. Bizarre isn't it ? I don't think that we will ever understand the convoluted thinking that goes on in big business, because being service people, we are basically practical and 'linear' thinkers. Seeing the 'bigger picture' is not something that engineers are good at, in my experience. Probably as a result of our job and training taking us down an ever narrower field of view towards our goal of finding the single component, or small group of components, that's at fault. I like to think of myself as a "man in business", rather than a "businessman". Arfa |
#17
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Is recession good for commercial electronic repair ?
Arfa Daily wrote: Just as an aside. I know how much you love valves ... Today, I had a Marshall on the bench. Pair of EL34s in the output. On the tester, it sounded awful, and the 'scope showed a highly assymetric output waveform. The drive to both outputs was fine, and the bias was correct on both valves. The waveforms on the anode of each valve looked pretty similar, but on the back side of the output tranny, it looked lousy. Both valves had screen voltage, fed via a 1k resistor each, but I noticed that the screen volts at the actual pin was 4 volts lower on one valve, than the other. When I measured actually across each screenfeed R, one of them had 4.4 volts across it, and the other had nothing. Turned out that the screen grid was open circuit on that valve. I hung a test one in there, and the voltage drop reappeared as it should, and the waveform on the output was now perfect. A new pair of valves and a bias check finished the job off. How unusual a problem is that ? In all my years of working with valves, I don't think that I can remember ever having had an open circuit screen grid. Can't say I have either. But then again have you ever seen 4 output valves go zero emission (this was in a Fender Twin Reverb). They were those dreadful Z&I Aero Services (Zaerix) Russian valves from the 70s/80s. Quite bizarre, all drive waveforms and bias voltages correct but no output at all. Incidentally I got it working because it was needed urgently by fitting 4 EL34s (I didn't have any 6L6s - you didn't see them much in the UK in those days). Graham |
#18
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Is recession good for commercial electronic repair ?
N_Cook wrote: Discuss Most stuff isn't designed to be easily repairable any more and replacing is so cheap that the question is largely moot. Graham |
#19
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Is recession good for commercial electronic repair ?
On Apr 18, 8:44*pm, "Arfa Daily" wrote:
It was a fairly 'new' tube as in 8 years or so, but an original Marshall factory fit. By new production I meant anything Russian, China, etc. made these days since tube production started shutting down in the 70s. The Slovak made "JJ" branded pwr tubes are very robust. I'll normally use them unless a customer specifies otherwise. As far as you could see looking through the glass, it was a 'genuine' EL34 pentode, rather than a 6L6 look-alike beam tetrode masquerading as an EL34. That would be a 6CA7. Some ppl prefer the 6CA7 to EL34s in Mar$halls. They're less "furry" sounding, kinda like a KT88's younger sibling. Original Sylvania 6CA7s can bring impressive money these days for NOS. The screen grid connection ribbon looked intact. Just for sport, I tried measuring the capacitance from the screen grid to the anode, and it measured exactly the same as on the opposite tube which was working, so that would indicate that the screen was in fact intact. Never-the-less, the bad tube drew no discernible screen current at all. The emission was pretty poor on both tubes, so about the only other thing that I can come up with is that the emission was so low on that tube, that the standing bias had it basically cut off, so the screen had no source of current to draw from. Arfa- Hide quoted text - - Show quoted text - |
#20
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Is recession good for commercial electronic repair ?
"boardjunkie" wrote in message ... On Apr 18, 8:44 pm, "Arfa Daily" wrote: It was a fairly 'new' tube as in 8 years or so, but an original Marshall factory fit. By new production I meant anything Russian, China, etc. made these days since tube production started shutting down in the 70s. The Slovak made "JJ" branded pwr tubes are very robust. I'll normally use them unless a customer specifies otherwise. As far as you could see looking through the glass, it was a 'genuine' EL34 pentode, rather than a 6L6 look-alike beam tetrode masquerading as an EL34. That would be a 6CA7. Some ppl prefer the 6CA7 to EL34s in Mar$halls. They're less "furry" sounding, kinda like a KT88's younger sibling. Original Sylvania 6CA7s can bring impressive money these days for NOS. It was a genuine EL34 as in that's what it's marked, but not all tubes marked EL34 are actually that inside, so I've read, although I don't usually look that close, when I replace them. An article that I saw on Wiki a while back, said that they were quite often actually beam tetrode electrode assemblies, not genuine pentodes with a wire suppressor grid, even though they were marked "EL34", so I guess that some 6CA7's might turn up marked as EL34s. Just dug it out the trash to have a look, and there's no place of origin on it, but I would guess that it's an eastern bloc job rather than a Chinee. Arfa |
#21
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Is recession good for commercial electronic repair ?
"Eeyore" wrote in message ... Arfa Daily wrote: Just as an aside. I know how much you love valves ... Today, I had a Marshall on the bench. Pair of EL34s in the output. On the tester, it sounded awful, and the 'scope showed a highly assymetric output waveform. The drive to both outputs was fine, and the bias was correct on both valves. The waveforms on the anode of each valve looked pretty similar, but on the back side of the output tranny, it looked lousy. Both valves had screen voltage, fed via a 1k resistor each, but I noticed that the screen volts at the actual pin was 4 volts lower on one valve, than the other. When I measured actually across each screenfeed R, one of them had 4.4 volts across it, and the other had nothing. Turned out that the screen grid was open circuit on that valve. I hung a test one in there, and the voltage drop reappeared as it should, and the waveform on the output was now perfect. A new pair of valves and a bias check finished the job off. How unusual a problem is that ? In all my years of working with valves, I don't think that I can remember ever having had an open circuit screen grid. Can't say I have either. But then again have you ever seen 4 output valves go zero emission (this was in a Fender Twin Reverb). They were those dreadful Z&I Aero Services (Zaerix) Russian valves from the 70s/80s. Quite bizarre, all drive waveforms and bias voltages correct but no output at all. Incidentally I got it working because it was needed urgently by fitting 4 EL34s (I didn't have any 6L6s - you didn't see them much in the UK in those days). Graham Yes Graham, I too have fitted 6L6's and vice versa. I have read on Wiki I think that EL34's turn up with 6L6 guts in them. I think that the beam tetrode structure was actually created to get around the patent that MO had on the EL34 pentode structure, so I guess it's reasonable that they should have similar characteristics. Crikey ! Z & I Aero Services aka Zaerix. That takes me back a bit. I still have a Zaerix shortform catalogue in pristine condition. Had some useful data in it, and ex military valves and 'scope / radar tubes ... Arfa |
#22
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Is recession good for commercial electronic repair ?
N_Cook wrote:
I would assume that breakpoint ratio moves towards favouring repair in resession. Only if wages drop or supply of replacements are affected. Someone was recently explaining that his job was really to disconnect the faulty module and connect the replacement module as everything in his mine was now "modularised" and encapsulated. Final act was to put the faulty part in the bin. |
#23
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Is recession good for commercial electronic repair ?
Arfa Daily wrote: "Eeyore" wrote Arfa Daily wrote: A new pair of valves and a bias check finished the job off. How unusual a problem is that ? In all my years of working with valves, I don't think that I can remember ever having had an open circuit screen grid. Can't say I have either. But then again have you ever seen 4 output valves go zero emission (this was in a Fender Twin Reverb). They were those dreadful Z&I Aero Services (Zaerix) Russian valves from the 70s/80s. Quite bizarre, all drive waveforms and bias voltages correct but no output at all. Incidentally I got it working because it was needed urgently by fitting 4 EL34s (I didn't have any 6L6s - you didn't see them much in the UK in those days). Graham Yes Graham, I too have fitted 6L6's and vice versa. I have read on Wiki I think that EL34's turn up with 6L6 guts in them. I think that the beam tetrode structure was actually created to get around the patent that MO had on the EL34 pentode structure I think you're right about that although the patent would have been on the KT66 I think. MOV never made the EL34 AFAIK. so I guess it's reasonable that they should have similar characteristics. Crikey ! Z & I Aero Services aka Zaerix. That takes me back a bit. I still have a Zaerix shortform catalogue in pristine condition. Had some useful data in it, and ex military valves and 'scope / radar tubes ... I recall their shop in Tottenham Court Road too. You could still browse surplus equipment back in those days. Imagine what those properties must be worth now ! Graham |
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