while trying to repair my Tek 2215 B-channel vertical preamp, I fell upon a transistor with this unusual (at least to me) designation. According to the service manual it is a small signal NPN type.
Google does not produce any usable results so I would appreciate any help to find a datasheet that will help me locate a modern equivalent for replacement
Google does not produce any usable results so I would appreciate any help to find a datasheet that will help me locate a modern equivalent for replacement
thank you Mooly. It is the one pointed by the arrow. Actually all Q257,258,267,268 are of the same type
what puzzles me is that SPS8223 and other similar types were used by Tek extensively in the 80's and yet I cannot find any data.
I guess I will have to take out a healthy one to measure the basic parameters. Most probably a BC5xx will do the job
what puzzles me is that SPS8223 and other similar types were used by Tek extensively in the 80's and yet I cannot find any data.
I guess I will have to take out a healthy one to measure the basic parameters. Most probably a BC5xx will do the job
well this also a confusing area. The service manual specifies all Q257,258,267,268 as SPS8223 NPN type while the schematic symbol for Q257 looks more like a PNP
just for the history and to the benefit of anyone with a similar problem in the future here's an update:
Channel B work great again!. The aforementioned transistor is a PNP as Mooly correctly pointed out and type is MPSH81. However this one proved to be okay, the culprit was U270D which is shown to the right of Q257 in Channel B vertical preamp section. This is one of 5 NPN transistors included in a CA3127E DIP16 transistor array.
I have no idea how this was fried especially since I do not use channel B often. Anyhow I managed to find NOS replacement (it took ages to turn up but that's another story) and after replacing, everything works great again.
The service manual proved of course invaluable in tracking down the problem
Channel B work great again!
. The aforementioned transistor is a PNP as Mooly correctly pointed out and type is MPSH81. However this one proved to be okay, the culprit was U270D which is shown to the right of Q257 in Channel B vertical preamp section. This is one of 5 NPN transistors included in a CA3127E DIP16 transistor array.I have no idea how this was fried especially since I do not use channel B often. Anyhow I managed to find NOS replacement (it took ages to turn up but that's another story) and after replacing, everything works great again.
The service manual proved of course invaluable in tracking down the problem
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