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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Old January 25th 10, 09:17 AM posted to sci.electronics.repair
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Default 68C diode from 1963

In 1963 JVC VN900 amp, circuit designation STV-3, probably a triple diode
for bias seting, any info on it?. Parts listing absent from the manual, just
68C on black body 4x7x10mm that looks like a slotted opto device but instead
of square bottomed notch , semicircle curved, as though for locating on a
rod, but mounted on pcb here.



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Old January 25th 10, 10:47 AM posted to sci.electronics.repair
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Default 68C diode from 1963

N_Cook wrote in message
...
In 1963 JVC VN900 amp, circuit designation STV-3, probably a triple diode
for bias seting, any info on it?. Parts listing absent from the manual,

just
68C on black body 4x7x10mm that looks like a slotted opto device but

instead
of square bottomed notch , semicircle curved, as though for locating on

a
rod, but mounted on pcb here.



Just found a side ref to it in the manual, a varistor, part number
E03094-002
circuit symbol 3 triangles in a row, like 3 diodes without 2 of the cathode
bars,
not skew Z over a resistor, or back to back triangles
Probably varistor diode but no useful data found yet , whether varistor or 3
diodes or varistor and 1 diode or whatever, or that symbol found elsewhere


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Old January 25th 10, 11:49 AM posted to sci.electronics.repair
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Default 68C diode from 1963

"N_Cook" wrote in message
...
In 1963 JVC VN900 amp, circuit designation STV-3, probably a triple diode
for bias seting, any info on it?. Parts listing absent from the manual,
just
68C on black body 4x7x10mm that looks like a slotted opto device but
instead
of square bottomed notch , semicircle curved, as though for locating on
a
rod, but mounted on pcb here.




I tried to email you some data on that diode but it bounced. You can email
me at



and reverse the domain to read "sbcglobal"

and I'll resend.

BTW I think the VN-900 was closer to 1970...

I own one, also a VN-700...

Mark Z.

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Old January 25th 10, 04:16 PM posted to sci.electronics.repair
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Default 68C diode from 1963

Mark Zacharias wrote in message
...
"N_Cook" wrote in message
...
In 1963 JVC VN900 amp, circuit designation STV-3, probably a triple

diode
for bias seting, any info on it?. Parts listing absent from the manual,
just
68C on black body 4x7x10mm that looks like a slotted opto device but
instead
of square bottomed notch , semicircle curved, as though for locating

on
a
rod, but mounted on pcb here.




I tried to email you some data on that diode but it bounced. You can email
me at



and reverse the domain to read "sbcglobal"

and I'll resend.

BTW I think the VN-900 was closer to 1970...

I own one, also a VN-700...

Mark Z.



All received, thanks.
Next task - to learn Japaneso



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Old January 25th 10, 04:50 PM posted to sci.electronics.repair
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Posts: 5,225
Default 68C diode from 1963

Mark Zacharias wrote in message
...
"N_Cook" wrote in message
...
In 1963 JVC VN900 amp, circuit designation STV-3, probably a triple

diode
for bias seting, any info on it?. Parts listing absent from the manual,
just
68C on black body 4x7x10mm that looks like a slotted opto device but
instead
of square bottomed notch , semicircle curved, as though for locating

on
a
rod, but mounted on pcb here.




I tried to email you some data on that diode but it bounced. You can email
me at



and reverse the domain to read "sbcglobal"

and I'll resend.

BTW I think the VN-900 was closer to 1970...

I own one, also a VN-700...

Mark Z.


I was taking 6303 on the Elno main caps as datecode , dark brown phenolic
pcb board, wire-wrap type wiring and some strange transistor packagings as
being consistent with 1963 but will burrow again

Not that 150A package but
Imax 120mA, Vr max 50V, Ir max 10uA, and at 7mA, 1.65V forward V, -7mV per
degree C

As one 1n4148 is about -1.6mV per deg C then 3 in series would be about
right forward V but not enough thermal response at -4.8mV , is Ge more
thermally responsive ? or some sort of NTC thermistor in there as well




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Old January 25th 10, 05:32 PM posted to sci.electronics.repair
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Posts: 5,225
Default 68C diode from 1963

1N4148 at 7mA would be more like -2.3mA per deg C so 3 x 1n4148 looks
suitable

No other datecodes found, so presumably ELNA QEY 6303 is a type number for
6800uF 63V electros.
Light grey cement/epoxy? cased resistors are more 70s than 60s
Some strange-to-me 2SC960 bolt-downable (but not here, like the varistors)
packages , different to my 1977 databook listing, but all types in here are
Si not 60s Ge


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Old January 26th 10, 06:26 AM posted to sci.electronics.repair
isw isw is offline
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Default 68C diode from 1963

In article ,
"N_Cook" wrote:

Mark Zacharias wrote in message
...
"N_Cook" wrote in message
...
In 1963 JVC VN900 amp, circuit designation STV-3, probably a triple

diode
for bias seting, any info on it?. Parts listing absent from the manual,
just
68C on black body 4x7x10mm that looks like a slotted opto device but
instead
of square bottomed notch , semicircle curved, as though for locating

on
a
rod, but mounted on pcb here.




I tried to email you some data on that diode but it bounced. You can email
me at



and reverse the domain to read "sbcglobal"

and I'll resend.

BTW I think the VN-900 was closer to 1970...

I own one, also a VN-700...

Mark Z.


I was taking 6303 on the Elno main caps as datecode , dark brown phenolic
pcb board, wire-wrap type wiring and some strange transistor packagings as
being consistent with 1963 but will burrow again

Not that 150A package but
Imax 120mA, Vr max 50V, Ir max 10uA, and at 7mA, 1.65V forward V, -7mV per
degree C

As one 1n4148 is about -1.6mV per deg C then 3 in series would be about
right forward V but not enough thermal response at -4.8mV , is Ge more
thermally responsive ? or some sort of NTC thermistor in there as well


Some diodes intend for temperature compensation used actual transistor
B-E junctions, to get a better match to the "real" transistors over
temperature.

Isaac
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Old January 26th 10, 11:40 AM posted to sci.electronics.repair
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Default 68C diode from 1963

Mark Zacharias wrote in message
...
"N_Cook" wrote in message
...
In 1963 JVC VN900 amp, circuit designation STV-3, probably a triple

diode
for bias seting, any info on it?. Parts listing absent from the manual,
just
68C on black body 4x7x10mm that looks like a slotted opto device but
instead
of square bottomed notch , semicircle curved, as though for locating

on
a
rod, but mounted on pcb here.




I tried to email you some data on that diode but it bounced. You can email
me at



and reverse the domain to read "sbcglobal"

and I'll resend.

BTW I think the VN-900 was closer to 1970...

I own one, also a VN-700...

Mark Z.


Presumably about 1973 made, from www cites, although I can find no indicator
inside the amp.
Can't find 6303 as an ELNA type number , so maybe old stock caps used.
Those 2SC960 with great bolt down mounting flanges, that are not bolted,
floating in mid air look mighty strange also , no package pic/type number
found for them, somewhere between TO3 and TO37 but flanges twice as thick
but TO5 size cap .
Amp serial number 046017**



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Old January 26th 10, 12:17 PM posted to sci.electronics.repair
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Posts: 115
Default 68C diode from 1963

"N_Cook" wrote in message
...
Mark Zacharias wrote in message
...
"N_Cook" wrote in message
...
In 1963 JVC VN900 amp, circuit designation STV-3, probably a triple

diode
for bias seting, any info on it?. Parts listing absent from the manual,
just
68C on black body 4x7x10mm that looks like a slotted opto device but
instead
of square bottomed notch , semicircle curved, as though for locating

on
a
rod, but mounted on pcb here.




I tried to email you some data on that diode but it bounced. You can
email
me at



and reverse the domain to read "sbcglobal"

and I'll resend.

BTW I think the VN-900 was closer to 1970...

I own one, also a VN-700...

Mark Z.


Presumably about 1973 made, from www cites, although I can find no
indicator
inside the amp.
Can't find 6303 as an ELNA type number , so maybe old stock caps used.
Those 2SC960 with great bolt down mounting flanges, that are not bolted,
floating in mid air look mighty strange also , no package pic/type number
found for them, somewhere between TO3 and TO37 but flanges twice as thick
but TO5 size cap .
Amp serial number 046017**




As a teenager in the '70's I used to like these models, (the VN-900 and
VN-700) but now as a technician I find they are really kind of junky as
regards the amp section and overall quality, compared to the Pioneer,
Kenwood, Marantz etc of the time.
Seems like they put a little too much of the manufacturing cost into the SEA
tone section.
Also, I find one can clean the controls until you are blue in the face, yet
within a couple months they are acting up again. I seem to have much better
luck on this with other brands.
My VN-900 has low level noise problems I have so far been unable to resolve.
Coupling caps, power supply, signal transistors, no luck. Had to set it
aside for some future date...

Mark Z.

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Old January 26th 10, 05:12 PM posted to sci.electronics.repair
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First recorded activity by DIYBanter: Jul 2006
Posts: 100
Default 68C diode from 1963

On Tue, 26 Jan 2010 05:17:53 -0600, "Mark Zacharias"
wrote:

"N_Cook" wrote in message
...
Mark Zacharias wrote in message
...
"N_Cook" wrote in message
...
In 1963 JVC VN900 amp, circuit designation STV-3, probably a triple

diode
for bias seting, any info on it?. Parts listing absent from the manual,
just
68C on black body 4x7x10mm that looks like a slotted opto device but
instead
of square bottomed notch , semicircle curved, as though for locating

on
a
rod, but mounted on pcb here.




I tried to email you some data on that diode but it bounced. You can
email
me at



and reverse the domain to read "sbcglobal"

and I'll resend.

BTW I think the VN-900 was closer to 1970...

I own one, also a VN-700...

Mark Z.


Presumably about 1973 made, from www cites, although I can find no
indicator
inside the amp.
Can't find 6303 as an ELNA type number , so maybe old stock caps used.
Those 2SC960 with great bolt down mounting flanges, that are not bolted,
floating in mid air look mighty strange also , no package pic/type number
found for them, somewhere between TO3 and TO37 but flanges twice as thick
but TO5 size cap .
Amp serial number 046017**




As a teenager in the '70's I used to like these models, (the VN-900 and
VN-700) but now as a technician I find they are really kind of junky as
regards the amp section and overall quality, compared to the Pioneer,
Kenwood, Marantz etc of the time.
Seems like they put a little too much of the manufacturing cost into the SEA
tone section.
Also, I find one can clean the controls until you are blue in the face, yet
within a couple months they are acting up again. I seem to have much better
luck on this with other brands.
My VN-900 has low level noise problems I have so far been unable to resolve.
Coupling caps, power supply, signal transistors, no luck. Had to set it
aside for some future date...

Mark Z.



Mark,

We used to have problems with noisy resistors in Japanese amps of that
vintage. In a pinch, for testing purposes, we'd stack 3 silicon
diodes to sub for a STV-3. If the STV3s aren't available these days,
perhaps mounting the diodes to a piece of aluminum and attaching it to
the heatsink might suffice. Chuck


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