Yeah... a dead-short in all possible directions is an easy test...
Aim towards being able to test a BJT that starts to oscillate, or starts to clip & cause distortions - when driven hard in a circuit, due to secondary breakdown, or other partial damage to one of its junctions. This is much more challenging.
Aim towards being able to test a BJT that starts to oscillate, or starts to clip & cause distortions - when driven hard in a circuit, due to secondary breakdown, or other partial damage to one of its junctions. This is much more challenging.
This is why it's ultimately heading to a shop....I'm limited(self limited) to testing components in circuit with a good multi-meter with out the unit powered up. I built a nice dim bulb tester, but at this point I am too cowardly(out of ignorance) to plug it in out of fear of causing more damage.
So, there she sits - on my bench all naked and stuff while I probe away. I've learned a lot over the last couple of weeks and it's been fun - that is why I'm still here asking questions.
So, there she sits - on my bench all naked and stuff while I probe away. I've learned a lot over the last couple of weeks and it's been fun - that is why I'm still here asking questions.
Well, of to the shop it went - back on June 4th. Just got it back yesterday.
16 weeks in the shop. I was about to jump in the car and just take it home since it was there for sooooo long.
The four power transistors in the left channel were replaced. The originals:
Sanken A1104(x2) and C2679(x2) were replaced with Sanken MP103S(x2) and MN103S(x2)
The guy at the shop told me the replaced then with new Toshiba parts. I guess he was a little mistaken.
16 weeks in the shop. I was about to jump in the car and just take it home since it was there for sooooo long.
The four power transistors in the left channel were replaced. The originals:
Sanken A1104(x2) and C2679(x2) were replaced with Sanken MP103S(x2) and MN103S(x2)
The guy at the shop told me the replaced then with new Toshiba parts. I guess he was a little mistaken.
Hi, didn't they replace anything else?? Seems unlikely that the output transistors just failed on their own, and without any collateral damage.
Also, are you sure about this: "Sanken MP103S(x2) and MN103S(x2)" ? - these type codes sound wrong..
Also, are you sure about this: "Sanken MP103S(x2) and MN103S(x2)" ? - these type codes sound wrong..
As a long time servicer, I've had stuff in my shop for weeks as well.
You have to understand that a busy shop, handling other customers stuff, as well as having to order (and wait for parts to come in, including backorders) takes time.
If any of my customers ever complained about the wait time, I politely explain this to them.
Those original output transistors could also have been subbed by a number of current Sanken types, assuming that's all the problem was. Take a look at this thread: 2SA1102 vs 2SA1104 with 2SC2577
I don't know where MN103S and MP103S type transistors come into this either - they don't appear in Sanken's catalogues so they must be from another source or those are house codes for a specific client.
I don't know where MN103S and MP103S type transistors come into this either - they don't appear in Sanken's catalogues so they must be from another source or those are house codes for a specific client.
This is a photo of the replacement output transistors.
The initial estimate for the repair was 6-8 weeks. No complaints, just stating facts. It's a good shop and they are very busy. Every time I called (past 8 weeks) it was stated that they were waiting on parts. I was told that they put in new Toshiba transistors - clearly not. They look used to me. If I were to guess, I'd say they came out of an old Onkyo. It was stated to me that they also replaced the drivers on that side and a cap. They also resoldered the ringed solder joints as they found them.
It works, and it sounds good. Just wondering how long those Sankens are going to last.
An externally hosted image should be here but it was not working when we last tested it.
The initial estimate for the repair was 6-8 weeks. No complaints, just stating facts. It's a good shop and they are very busy. Every time I called (past 8 weeks) it was stated that they were waiting on parts. I was told that they put in new Toshiba transistors - clearly not. They look used to me. If I were to guess, I'd say they came out of an old Onkyo. It was stated to me that they also replaced the drivers on that side and a cap. They also resoldered the ringed solder joints as they found them.
It works, and it sounds good. Just wondering how long those Sankens are going to last.
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Type codes corrected above - they are 130s NOT 103s - mistype on my part.
See attached photo above. I'm guessing those 130s were either NOS or came out of another unit - maybe Onkyo?
I'm pretty sure he said he also replaced the drivers but they are difficult to see/photo and are shrouded by small heat-sinks. He also said he replaced a cap and repaired all of the ringed solder joins he could find.
I see some wiring is of the "wire wrapped" type.
I've never liked that style of assembly, it was a "trend" back years ago, and I don't like trends, I liken them to fads, also disliked.
Anything that came in the shop that way, I soldered those wires to the posts.
A dab of solder at the top of the wrap is sufficient.
Almost all of the board to board wiring is done by using wire wraps on posts in this unit.
It would have been nice if they had "modularized" all of these wire connections such that boards could be easily isolated, removed, and repaired.
It would have been nice if they had "modularized" all of these wire connections such that boards could be easily isolated, removed, and repaired.
Yes, it would have been nice.
But like I mentioned, it was a "trend" years ago, and I hated it in the shop when I had to manipulate boards/parts during servicing.
It just adds to the "labor-frustration costs" that I imposed on such products.