Samson XM610 powered PA

[nosaj]

I've got a Samson XM610 Powered PA. It was given to me to work out for practice.
In checking out the power supply. It is unloaded not connected to any of the power amp boards.

CN104 and CN204 The Rails are 73.6 +- on both Schem says +-82vdc(loaded).
Aren't unloaded voltages generally higher? If so does that tend to says weak filter caps.

Thanks,
nosaj

[The Dude]

That's not generally something I'd worry much about unless there are related symptoms. Does it hum? What are the symptoms? What are you trying to fix?

[g1]

Can you post the schematic.
If the low rail voltages are due to caps, you should see significant AC voltage across them.

[nosaj]

That's not generally something I'd worry much about unless there are related symptoms. Does it hum? What are the symptoms? What are you trying to fix?

There was no output on it. It was someone else's repair that wasn't paid for. So I got it for peanuts and practice.
I thought I'd start at the front end and make sure the power supply was putting out correctly. I've just pulled all the out puts and testing them out of circuit.
nosaj
Samson XM610 PA.pdfSamson XM610 mixer.pdfSamson XM610 PS.pdf

[nosaj]

Can you post the schematic.
If the low rail voltages are due to caps, you should see significant AC voltage across them.

With a load or without a load? Schems posted.
Thanks,
nosaj

[The Dude]

FYI: Those schematic links are dead (at least on my computin' box).

[nosaj]

FYI: Those schematic links are dead (at least on my computin' box).

i found 3 dead SC5200 1 sa1943 and 1 c4370A on CH1 and CH2. I have good spares to sub in after checking the resistors

Hopefully this is acceptable.
http://music-electronics-forum.com/t26557/

Thanks,
nosaj

[The Dude]

Direct Link:

http://music-electronics-forum.com/a...mson-xm610.zip

[nosaj]

i found 3 dead SC5200 1 sa1943 and 1 c4370A on CH1 and CH2. I have good spares to sub in after checking the resistors

Hopefully this is acceptable.
http://music-electronics-forum.com/t26557/

Thanks,
nosaj

Tested with Simpson 260 on 10k just ran through all the resistors looking for continuity These I found bad. On the Schematic Some are listed FR 47 I believe is Fusible Resistor 47 ohm?
Testing the resistors amp1 r157, R145, r150, r162, r143
Amp2 R250 R262 R245, r240


Came up short on a C4370A. Gotta keep digging.


Thanks,
nosaj

[The Dude]

2SC3298 should work for 2SC4370.

[nosaj]

2SC3298 should work for 2SC4370.

I'll have to see if I have one of those or not. FR stands for Fusible resistor correct? What is that a 1/16th watt resistor?

Also ran out of time also have to check q121 q122 and q221 and q222.

Thanks,
nosaj

[The Dude]

Hard to say for sure what you have there without seeing it or having a parts list. I imagine it's something like this:

http://www.mouser.com/ProductDetail/...%2fnNK5PfdXrY=

[Enzo]

Fusible means it will open rather than go up in flames. It does not mean tiny so it wil burn out easily.

82v 73v, doesn't matter. 10% low on main rails is not gong to make the output disappear.

Fix what is wrong, update caps later.

[nosaj]

Hard to say for sure what you have there without seeing it or having a parts list. I imagine it's something like this:

http://www.mouser.com/ProductDetail/...%2fnNK5PfdXrY=

Here's what I have with a 1/2watt beside it.

I'll have to order some all I have are 1/2 watt ones no Fusible Resistors in my stock.

Thanks,
nosaj

[nosaj]

Fusible means it will open rather than go up in flames. It does not mean tiny so it wil burn out easily.

82v 73v, doesn't matter. 10% low on main rails is not gong to make the output disappear.

Fix what is wrong, update caps later.

I'm not sure what wattage to get . Is it possible the color code on the resistor might tell? I found them on mouser they're 2 watt ones though. I try the color code and see.

Thanks,
nosaj