problem with a ms-275

[unbreakabledancer777]

Hello everyone, sorry if I do not speak English very well but I do my best.

I have a PG-275 ms, unfortunately it seems to have a problem.

I plugged it and the light green (on) turns on then turns off and red light (overload) lights and turns off intermittently with each other.

I know what it means according to the manual but neither option is my case.

Version of this amp is white.

Finally, I looked at the connections inside the amp and I noticed that the B + from the inlet and connected around a spool is properly screwed on the amp, just for the B-but B- I noticed that the screw has been damaged, it is more like those backgrounds (I mean intact) because I bought this amp on ebay a few years ago but has already turns, I do not remember having had this problem before, can you help me please?

In advance thank you

[unbreakabledancer777]

Up

[joerg]

Quite hard to tell without any pictures of the circuit board. Upload a few high res ones to let the electronic gurus look for damages u don´t notice.

[unbreakabledancer777]

Ok I will make it quickly

[freshkryp69]

I rec you contact the Eric d on this forum, he can repair and refurbish the amplifier to equal to or better than new specs , your choice. the capacitors in the amp (before it catches fire), need to be replaced BAD, if its OG then its a must. it will last for another 20 yrs. all OUR old school M,MS,MPS,ZPA series of amps need this done. its like changing the oil in the car...or eating..

[unbreakabledancer777]

ps: I' m from Belgium, I have a ms-2125 older and he's always running at it best

[unbreakabledancer777]

I didn't know that but I live in Belgium, how can I could replace the caps here?

[Mr. Wild]

Looks like the big capacitors have been changed. They are originally 4700uF.

[unbreakabledancer777]

I don't know but if you say it, I believe you.

and the three others?

[wooferdog]

a picture from the side with the numbers on the 3 smaller caps will help to know if they are stock or newer.

[unbreakabledancer777]

Here it is

[Eric D]

I would start by checking the parts on the heatsink marked 2SA1302, and 2SC???? (can't see the whole part number from your photo) for shorts. If one of these is damaged, it will cause the amp to power on and then overload.

If these are fine, you can then move onto a few other parts near them which may be damaged.

[Mr. Wild]

The stripes on the original 3 power supply caps are much yellower than in your pics. That and the fact that the big rail caps appear to be new, leads me to think your power supply caps have been changed too.

Here's a pic of my MS275 original caps.

[unbreakabledancer777]

Here it is, do you think they seems damaged? I take pictures of the other transistors, can you say to me if they are originals?

Someone says to me that my transistors are placed obliquely, and someone has redone welds, can you confirm that?

[unbreakabledancer777]

The stripes on the original 3 power supply caps are much yellower than in your pics. That and the fact that the big rail caps appear to be new, leads me to think your power supply caps have been changed too.

Here's a pic of my MS275 original caps.

Can you say to me what is the black lign on the left ? I don't have that one

[Eric D]

Your amp looks very original to me. It is possible the large 15,000uF rail caps are not original, but I have seen some odd things in PG amps before, from the factory. The soldering job on the underside of the board would probably tell the full story.

The large black item you mention in your last post is just an aluminum clamp used to hold the transistors to the heatsink. PG started using these in later designs, but there is nothing wrong with your amp not having them.

[unbreakabledancer777]

Ok, so ...

If I have to replace something, I want it to stay true to the original model.

I also need to know how many uF for large and small caps and volts for large and small also, I want to be sure these specifications, so that my amp respects the original manufacture.

And I want to know which manufacturer should I buy these caps, which is the best in quality and durability?

Thank You

I have seen some odd things in PG amps before, from the factory

What do you mean about that?

________

I have a plexi on my ms-275 but I think it is not original at all:





and a screw is missing

And last thing I want to know is : there is a blue swith in the PG, what is it?

[unbreakabledancer777]

Up

[Mr. Wild]

Don't worry about the blue master / slave switch. It is used when you use several MS amps at the same time. It synchronizes the power supplies switching frequencies or something.

The red / yellow switch inside the amp is for lowering the amps rail voltage if you use low ohm loads (2ohm bridged). Yellow is normal position, red is low voltage position. You can use the low voltage position if your amp keeps overheating.

[unbreakabledancer777]

ok and for the caps?, ELNA good manufacturer? and plexyglas?

Why there is a white and a grey series?

[Mr. Wild]

I'm pretty sure your MS-275 already has new caps.

[unbreakabledancer777]

maybe but the big caps are not of 15 000 originally, here This man have 15000 too (http://www.soundbuggy.com/Eric/Car%20Au ... index.html), don't like that, I would like to know what µF the ms-275 have originally; can you say what caps manufacturer is good for my PG's? ELNA? NICHICON?
And for my plexyglas?

I'm pretty sure that the problem is from the transistor but I want to know what material can I buy to change caps if I must do this in the future, cause I have a ms-2125 with original caps too.

[unbreakabledancer777]

up!

[unbreakabledancer777]

can anyone help me to finish this post please?

[nico boom]

If you look for it, you'll find the section where the right values are mentioned. [Nichicons] Guess somewhere in the how-to section.
If you need help with recapping I could maybe help out, I've done a few.
Also got two new original metal bottoms, white. And you're from Belgium, so we are neighbours.
Spreek je Nederlands overigens?
Nico