MS-2125 Amp fuses question

gothpunk4christ · Post by **gothpunk4christ** » Sat Nov 06, 2010 1:08 pm

I received this amp from a friend who said it didn't work. It looks like the main issue is that 2 fuses need to be replaced/installed. I've done a few searches and haven't been able to find a schematic.

Here's a picture of it and the 2 fuses I need are on the far right side. They are the larger fuses, not the smaller ones.

MS-2125

Post by **ttocs** » Sat Nov 06, 2010 2:14 pm

are the diods between them burned up or have they been replaced?

gothpunk4christ · Post by **gothpunk4christ** » Sat Nov 06, 2010 2:16 pm

I'm not sure. Those Zener diodes, it appears to just be rosin.

Post by **joerg** » Sat Nov 06, 2010 2:20 pm

The fuses are 40 Amps

gothpunk4christ · Post by **gothpunk4christ** » Sat Nov 06, 2010 2:21 pm

joerg wrote:The fuses are 40 Amps

Awesome. 120V?

valeks1 · Post by **valeks1** » Sat Nov 06, 2010 2:25 pm

AGU Type 40A. If you need I think I have.

gothpunk4christ · Post by **gothpunk4christ** » Sat Nov 06, 2010 2:27 pm

valeks1 wrote:AGU Type 40A. If you need I think I have.

Ah, well I appreciate it! I have several resources though I should be able to find something. If I have any trouble getting them I'll give you a holler!

gothpunk4christ · Post by **gothpunk4christ** » Sat Nov 06, 2010 3:25 pm

32VAC it appears.

oldschoolfan · Post by **oldschoolfan** » Sat Nov 06, 2010 3:52 pm

Sure looks like someone dumped some solder on those diodes. Caps look original too.

gothpunk4christ · Post by **gothpunk4christ** » Sat Nov 06, 2010 3:57 pm

oldschoolfan wrote:Sure looks like someone dumped some solder on those diodes. Caps look original too.

Yeah I really don't know any of the history behind this amp. Guy said it worked for a while in his truck but then it stopped and he got another amp. I'm gonna go back over a lot of the board and clean up what looks to have been spilled (same method I fix all those water damaged iPhones with) and keep tracing voltages over the board to see what else I can figure out.

I haven't used much of my electronics knowledge in quite some time but I still remember enough to break something worse.

oldschoolfan · Post by **oldschoolfan** » Sat Nov 06, 2010 5:16 pm

It is always strongly suggested by most on this site to replace the input caps if they are original. They have a bad history of leaking, whether or not you can see leakage, so they need to be replaced to prevent a fire in your car. Not trying to scare you, just very important preventive maintenance. If you look around there are a ton a threads here about it, some great pics of damage that can result as well.

Here is an offsite link of a repair a regular on this site did, very informative.

http://www.soundbuggy.com/Eric/Car%20Au ... index.html

gothpunk4christ · Post by **gothpunk4christ** » Sat Nov 06, 2010 5:26 pm

Hey I really appreciate all the information. I haven't measured the zener diodes yet to see if they are still good or not.

I imagine I'll need to keep the same capacitance or is there a suggested replacement, and that's only for the front capacitors, not the larger blue ones?

Post by **ttocs** » Sat Nov 06, 2010 6:21 pm

no the big ones are the ones you need to worry about. I have an amp I am repairing now that a cap blew up on and they take part of the board with them when they go.

gothpunk4christ · Post by **gothpunk4christ** » Sat Nov 06, 2010 6:23 pm

ttocs wrote:no the big ones are the ones you need to worry about. I have an amp I am repairing now that a cap blew up on and they take part of the board with them when they go.

Ah, so I should just probably replace all of them then? lol. The images from the link above made me under the impression that the larger ones were ok.

oldschoolfan · Post by **oldschoolfan** » Sat Nov 06, 2010 6:30 pm

Usually the larger blue caps, the rail caps, are fine and don't need replacement. The twelve for the power supply are the ones you need to do for sure. The current caps available for the power supply that match the original specs are about a third the height of the originals. For this reason you can get caps that are the same size dimensionally as the originals but with higher capacitance. You can change these to higher capacitance without issue, you just wouldn't want to go lower than original specs. Originals are 16 volts and 2200 micro farads.

Read through this thread, it has some of the caps listed that are commonly used for this preventive maintenance.

http://phoenixphorum.com/ms-capacitor-r ... t9930.html

gothpunk4christ · Post by **gothpunk4christ** » Sat Nov 06, 2010 6:32 pm

Awesome. I tried doing a search but I have a bad habbit about not typing the exact words I need to get legitimate and useful results.

I'll dig thru that forum asap, I'm really enjoying the poeple here on this forum too lol. Useful and informative, and quite nice as well.

oldschoolfan · Post by **oldschoolfan** » Sat Nov 06, 2010 6:37 pm

Glad to hear it, welcome.

Post by **ttocs** » Sat Nov 06, 2010 7:56 pm

if yer gonna replace some caps why wouldn't you do them all?

Thunderdome · Post by **Thunderdome** » Sun Nov 07, 2010 3:35 pm

gothpunk4christ · Post by **gothpunk4christ** » Sun Nov 07, 2010 7:30 pm

ttocs wrote:if yer gonna replace some caps why wouldn't you do them all?

Good point, but I'm one of those "if it aint broke don't fix it" kind of people.

Or in this case "if it's not bound to break soon, only fix what will go out soon"

I may have to see about it though.

gothpunk4christ · Post by **gothpunk4christ** » Sun Nov 07, 2010 8:15 pm

On further inspection, and a taste test, it looks like the spill that I was noticing on the board, is actually the capacitors leaking... I'm currently going over it with some isopropyl, seeing what I can clean off (its taken off quite a bit)

I am wondering though, there's a connector for a fan... has anyone tried installing one on this amp? I wanna see pictures!

..... and no I didn't actually taste the stuff.

gothpunk4christ · Post by **gothpunk4christ** » Sun Nov 07, 2010 8:34 pm

Looks like someone previously attempted repair on this amp and did a shoddy job at it. Most of the transistors on the side are unscrewed and looks like a couple of them are even broken. Bah.

Post by **ttocs** » Sun Nov 07, 2010 9:05 pm

that was unfortnatly what I suspected with the bad solder job on the resistors.

gridracer · Post by **gridracer** » Sun Nov 07, 2010 9:59 pm

I might have some parts for you I have a ms2125 parts board. show pics of what you need. Or you can send it to valeks1 he used to be a pg repair tech and probably can refresh it like new. Alo drfosgate on here does repairs.