Cant get my blue ray working because of amp. Anyone ?

[alexk0il]

Four hours with screwdrivers, wrenches, one Styrol cap on AM/FM receiver board is accidentally broken, but I still don't have access to the main board or to the transformer.

Oh dear, these vintage amps were supposed to outlive the human race after a nuclear war.

[snowman_al]

''Oh dear, these vintage amps were supposed to outlive the human race after a nuclear war.'' - Sorry, no only the valve ones survive the atomic pulse!

It's all part of the fun...

Posting a picture(s) might help. There is little on the web to look at with respect to your version.

[alexk0il]

''Oh dear, these vintage amps were supposed to outlive the human race after a nuclear war.'' - Sorry, no only the valve ones survive the atomic pulse!

Thought he capacitors might leak before the nuclear war though... But mechanically wise it will be intact.

Posting a picture(s) might help. There is little on the web to look at with respect to your version.

All my photos are related to cages, covers and to the web of connectors that hold everything intact. I am sure I will fully enjoy working on glued three legged capacitors, I guess I will have to break them before de-soldering. But I might be "lucky" to discover the broken unobtanium transformer which I suspect can justify binning the amp and saving the pain

Anyway, I only took photos of the screws and connectors, not sure if these are interesting to anyone. Here are the photos of my and a very similar SR-2010 amp (it has one extra capacitor in the PSU and bigger/better heat sinks) from a German forum.
https://translate.google.com/transla...185-12766.html

[snowman_al]

Umm, I see the problem.
The primary windings are on top and the secondaries are hidden away down below. And no real markings to identify the numbers from the diagram, doh.

If yours is the same configuration as the pictures then it might be easier to remove the primary winding wires instead. And leave the secondaries in place.
Could you un-solder the 6/7 wires from the top of the transformer? Brown (9) white, red/red, blue, yellow and black (2). Make sure you note the positions very carefully before you start.

Then do the resistance test between pin 9 (Where the brown wire comes from) and any of the secondary terminals 21 to 26, and again from 9 to either 28 or 29 the bulb winding. Now go from pin 6 (where the red wires were) to any of the secondaries 21 and 26 and then 28 or 29 again. (As there are 2 primary windings so you have to test them both...) Then the short to core test as previously described.

Hope the colours and locations on yours are the same as the pictures.

Fix this before worrying about the caps ehy?

[alexk0il]

Finally found time to work on this... A bit of unsoldering, a bit of unscrewing and I managed to remove most of the front panel and the back sides of the case. I'm still puzzled though the back panel, can't figure out how to undo a couple of connectors before removing the back panel.

Anyway I followed your advice and tested the transformer with primary winding unsoldered:

• Both 6 and 9 give infinity readings to all secondary terminals.
• Gnd to 6 or to 9 - infinity
• Gnd to 28, 29 - infinity
• Gnd to all terminals form 21 to 26 - shirt circuit.

Don;t understand the last measurement. Perhaps I damaged something on electronic boards during the disassembly.

[snowman_al]

All those readings look good.

- Both 6 and 9 give infinity readings to all secondary terminals. = No primary to secondaries short.
- Gnd to 6 or to 9 - infinity = No primary short to ground.
- Gnd to 28, 29 - infinity = No 'bulb' winding short to ground.
- Gnd to all terminals form 21 to 26 - short circuit. = This is correct. Pin 23 is connected to the ground terminal and effectively 'ground' 21 to 26 due to the low resistance of the winding.

It almost proves the transformer is OK. Almost, because it may only breakdown at mains voltage. The voltage used by your meter will only be 9 volts max.

Next eliminate the wires from the mains to the transformer. Meg ohm resistance check again, case ground to each of the wires you removed from the transformer. Make sure to test with the power switch off and on.

[alexk0il]

power switch off and off: gnd to all removed wires shows open circuit


I'm confused... Since there are no issues with the transformer and with the unsoldered wires does it mean that the problem is gone? I don't think the 9V of the meter can be blamed, I could see the 6Ohm between Gnd and the other check points using the same multimeter.

May be Gnd is not supposed to be connected to terminals 21-26 and the problem is still there. I can't actually trace in the schematics how the gnd is connected to 21-26. Some diagrams show it is connected on a US variant and not on Asian and Latin American.

Another explanation is that I removed the case, front panel and had to disconnect a few wires between the front panel, main audio board and front-panel LED board. Perhaps this explains the good reading on my meter...

[snowman_al]

''I'm confused...'', me too, but that is how these faults go sometimes.
So far you've proved there is nothing obviously wrong! Maybe there was a blob of solder or strand of wire in there that has now fallen out? 50/50 chance I guess.

I think the case or chassis Ground comes from pin G1 (top left on the Tuner PWB)?

Image removed no longer needed.

It is tricky to follow, but it does eventually end up back at pin 34 on the Audio PWB and that is wired to number 23 (the low voltage centre tap) on the transformer. It is difficult to trace these without the boards in front of you. But you should be able to follow it through the circuit boards with your meter.

''I don't think the 9V of the meter can be blamed'', no the meter is fine. The problem is a 9 volt meter does not put any stress on a 'leak' between two windings or wires if they only 'break down' at mains voltage.

Without knowing exactly how far you have it apart, it is difficult to advise what to do next apart from putting it back together temporarily and trying it again.

I would strongly suggest that you fit a proper mains earth wire, at least as thick as the live and neutral wires, from the case ground terminal to the mains plug earth pin, before any further full voltage tests. If you look at the diagram again you will see the European version with the 3 core mains lead connects the earth to the chassis (the little brush symbol).

[alexk0il]

Thanks, I managed to find other connectors to Gnd close to speakers, and somewhere in the middle of the board and missed the G1

I'm not saying the meter is not fine, i'm just saying that since we did see the problem with the meter, I would expect the same problem to show up after desoldering. Whatever it was the meter was fine to pick it up.

I will try to find the way to attach the earth wire when I am done, though the Asian/Latin american power board might be different and not have the connectivity to the grround. I will simply attach a proper lead to one of other Gnd terminals (Green wire on the LED PCB board on my photos).

I think I will try to reconnect all desoldered wires back to confirm that the problem has gone and then i will proceed with recapping.

Here is where I am currently stuck. i am still struggling to remove the back-panel. Will show in the next post what i stopping me.

[alexk0il]

I can't figure out my way around antenna's connectors. How do i remove them?
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