I have just acquired an electrohome sr-2100 stereo receiver . the problem is that only one channel is working , I am trying to replace the output power transistors and I cannot find any information on them , this receiver uses the Motorola SJ5564 transistor .
does any one out-there know anything about these transistors !
is there a substitute for the sj5564 ? google searches on them comes up zero .
any help would be greatly appreciated , this is a beautiful receiver and I want it back in 100% working order .
does any one out-there know anything about these transistors !
is there a substitute for the sj5564 ? google searches on them comes up zero .
any help would be greatly appreciated , this is a beautiful receiver and I want it back in 100% working order .
Did you ever got it fixed. That number does not ring a bell. I believe each channel has 2 transistors on the heatsink one would be npn and pnp. What are the other numbers of the transistors? Taking photos would help. I've fixed a few Planar gear before.
Hi,
I have one of these Planar SR-2100. The amp is quasi complementary or what they call in their brochure "semi complementary".
Most likely MJ 15003 would be good replacements . For what it's worth , this is a very good sounding unit. I could never find any schematic anywhere btw.
Cheers
I have one of these Planar SR-2100. The amp is quasi complementary or what they call in their brochure "semi complementary".
Most likely MJ 15003 would be good replacements . For what it's worth , this is a very good sounding unit. I could never find any schematic anywhere btw.
Cheers
I've just uploaded SM to hifiengine, should be available shortly.
Any idea on the actual output transistor replacements? Mine has four Motorola, two of which need to be replaced. I couldn't find reference/replacement to 601-34.
Any idea how SJ5564 and the MJ 15003 were selected as match?
Any idea on the actual output transistor replacements? Mine has four Motorola, two of which need to be replaced. I couldn't find reference/replacement to 601-34.
Any idea how SJ5564 and the MJ 15003 were selected as match?
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Just 45, or does that mean 90? Makes A big difference. If that’s a 45 volt single supply just about any of the old 100W Moto parts would work (even 2N3055), but parts like the 2N587* or 8* are “better” in audio apps - gain tends to be higher than 3055’s. Of course the 15003 will work. If it’s +/-45, they’re probably MJ802’s or 2N5630. In that case you need the 15003.
Assuming +/-45, could an MJ10001 be used? Pc is 175W vs 200W and hFE 40 vs 25 but I have several on some other scrap boards I could try out.
Aren’t the MJ1000x series darlingtons? And have almost non-existent SOA because they’re for switching. Some of those early types HAD that low an hFE at full current.
You are correct. I hadn't looked well enough at the specs. They are on some boards of unknown origin that came in an auction lot from years ago. Looks like I'll need to order something.
So, I checked other transistors and output resistors and the only other one that seems off is the bias transistor for right channel - hfe > 700 and ic about 3 which is off from everything else. No idea what a replacement would be.
The really odd thing I don't understand is that after testing things and with the two power transistors pulled, I powered on with DBT and no fuse popped from shorted outputs as expected. However, when I plugged in headphones to see what the issue with tuner was, I had sound (static) from both channels. I plugged into the aux and sound from both. Checked for DC on speaker outs, was fine, so hooked up speakers. I have sound from both speakers. I don't understand how things are working. Any ideas?
The really odd thing I don't understand is that after testing things and with the two power transistors pulled, I powered on with DBT and no fuse popped from shorted outputs as expected. However, when I plugged in headphones to see what the issue with tuner was, I had sound (static) from both channels. I plugged into the aux and sound from both. Checked for DC on speaker outs, was fine, so hooked up speakers. I have sound from both speakers. I don't understand how things are working. Any ideas?
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FYI - great news! The schematic part that I was missing is available in AK database along with part list.
The transistor for bias circuit I am looking for is a small signal transistor.
And the voltages on schematic match what I measured on transistor.
I think I can figure out a replacement, but recommendations are welcomed.
The transistor for bias circuit I am looking for is a small signal transistor.
And the voltages on schematic match what I measured on transistor.
I think I can figure out a replacement, but recommendations are welcomed.
