the 2 bias pots where turned down all the way. I turned them up until the point I can see that there is a peak moment in amp use, the point that the BJT's are coming to live. Don't know a better way to explain this. Now the amp is pulling around 5A. But the overload LED is still on. So what happens ...

is it usually so that the 2 green LED's and red LED are turned on the same time? The green on LED should be out as the red LED is turned on, not?

changed the LM393 and the green led's are working but now the red overload LED is activated. The 4 bias LED's are working. I have no shorts in the output transistors but one IRFZ44 of the voltage regulators is shorted (Q32). Replaced al 4 of them. The red overload LED is still active. Pfff my motiva...

you wil not hear the difference

think I found the problem. I was so focused on the control board but the problem is not on this board. The problem is on the fan board. The fans are working so that is why I skipped this at first. There is also a LM393 on the fan board in the right corner that is getting the 15v from the same circui...

I have 3V where I should have 15v so something is pulling it down

this system has everything to sound top notch!
Where did you find these amps in this condition?
Hope you changed the power supply caps...

did find some time to continue with this repair. I did change all the broken diodes and resistors + I changed the KA339. Put the board back in the amp and powered up the amp. result: the 4 bias red LED'sare working + the 2 fans but no green LED's on the vertical board. I measured the voltage over th...

is the MS1000 sold?
was to expensive for me... I live in Europe that is asking price + shipping + 33% tax

start with the 10 0.51Ohm 1W resistors. If these are ok start with everything that is connected wit the 2 LED's. You said that the 2 front channels are working so it has to be in the 2 rear channels. Sart with the resistors and then the diode's. If you have a magnifying glass use it. If a resistor i...

First of all there are other forum members who have many, many more knowledge about these amps than me. I'm also in the learning curve but anyway I will try to help you before the other members chim in. Are you the first owner of this amp or not? The 2 red LED's are part of the bias circuit. You hav...

Hello and welcome on the forum!
is the Green LED light up?

ttocs wrote:https://www.facebook.com/groups/1473298426288964/

Hi ttocs, I tried several times to become member of this group but it doesn't work. Status says "in treatment"

Hi Jason! thank you so mush for this info. Now I can start finding the problem. The vertical boards are original V2 versions, I don't know why the first owner replaced so much components, I guess he handled the trial and error route. Do you have a link to the FB page? I did a search but cant' find i...

starting restoration...

some pictures when the amp just arrived...

hello Ttocs!

the switch is not in it's bypassed...

Long time ago I bought this amp on a second hand site. It's a standard V2 version.The outside of this amp is like in new condition. Also the plexiglas is in top condition. This is what convinced me to buy this amp. I payed the top price for this amp. When the outside is in top condition after al the...

found the tutorial from Eric about the pot meters.
Thank you Eric for your countless contributions to this forum.
It's a wonder that even after 8 years this info is still here.

The parts from Digikey arrived and the flat cable is replaced. Today I powerd up the amp and it plays wonderful! Just the sensitivity pot is giving a lot of distortion when you turn it up or down. Once it is set correctly it works fine. There is another post from zztunnell who has the same problem s...

Hello Eric! Thank you for the info but I want to keep the repairs as close as possible to the original. Thank you Jason for the part number, this saves me a lot of time with the search module.

The corrosion is caused by leaking PSU caps. Half of the pins of the vertical pcb are also very bad corroded. So I took out the vertical pcb and cleaned the pins and through holes. After putting everything back the power supply is working! By doing this I damaged the flat cable between X-over and ma...

Think I find the problem. Lilviper you where right! Because I knew it was in the power supply region I checked all the paths wit a magnifying glass and guess what. Few inches away from the sg3525 there was a place where 2 diodes, 2 resistors and 2 caps that had bad connections to the board. Because ...

Today I removed the 2 diodes that separate the power supply and the outputs. The 2 diodes test ok. When I power up nothing changed (fan is running and red LED burning) so I think that the problem is in the power supply section. I changed the SG3525 controller because I have no 6V on the gates of the...

what about the transformer: is it normal that when the amp is not powered up the windings are shorted?
Below is a picture, the red = shorted