Hello,
A friend of mine just got for me a broken Cambridge Audio A500 amplifier.
It's history is simple, ex-owner cranked the volume way up and it just died.
Now, the culprit should be the SAP15 output transistors. They usually are.
I will put my hands on the unit tonight and I will test some more to see exactly what's what.
Usually the internal 0.22R resistors fail before the transistor does.
If they fail, I presume they fail open circuit? Could I just add a set of 0.22R resistors on top of them (cut the leg from the transistor etc).
As I see the replacement would be STD03 N/P.
I want to know if there are any European suppliers for these parts. I checked on Farnell/TME and couldn't find them.
A friend of mine just got for me a broken Cambridge Audio A500 amplifier.
It's history is simple, ex-owner cranked the volume way up and it just died.
Now, the culprit should be the SAP15 output transistors. They usually are.
I will put my hands on the unit tonight and I will test some more to see exactly what's what.
Usually the internal 0.22R resistors fail before the transistor does.
If they fail, I presume they fail open circuit? Could I just add a set of 0.22R resistors on top of them (cut the leg from the transistor etc).
As I see the replacement would be STD03 N/P.
I want to know if there are any European suppliers for these parts. I checked on Farnell/TME and couldn't find them.
Thank you for the info.
In the meantime I found them on Profusion plc, Audio Semiconductors and Components with 5 euro shipping, and with two pairs and shipping I still get under the price of one pair without shipping from your source.
Also I don't usually trust ebay for transistors, I got burned a couple of times already.
In the meantime I found them on Profusion plc, Audio Semiconductors and Components with 5 euro shipping, and with two pairs and shipping I still get under the price of one pair without shipping from your source.
Also I don't usually trust ebay for transistors, I got burned a couple of times already.
A bit off topic:
I measured the CE junction and there's no short on any output transistor.
Also all the emitter resistors check for 0.22R
Would these two checks rule out the outputs? Before I dig deeper and start taking out the boards.
I measured the CE junction and there's no short on any output transistor.
Also all the emitter resistors check for 0.22R
Would these two checks rule out the outputs? Before I dig deeper and start taking out the boards.
I powered it, and all PS voltages check out fine.
Bias voltage on the emitter resistors checks find at 13mV as per manual.
I will inject a signal and see if I have any outputs. Maybe I don't need the transistors after all 🙂
Bias voltage on the emitter resistors checks find at 13mV as per manual.
I will inject a signal and see if I have any outputs. Maybe I don't need the transistors after all 🙂
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