Channel on M44 crackling (now with pics)

paulbfd · Post by **paulbfd** » Tue Aug 14, 2007 11:19 am

Finally got round to fitting my M44 & M100, but one of the channels on the M44 is "crackling".

It's only faint and doesn't get any louder when you turn it up.

Any ideas?

Is about to go up in flames?

twisted · Post by **twisted** » Tue Aug 14, 2007 11:28 am

man that thing is toast!!!! you had better give it to me

j/k

1moreamp or ericd would have a good awnser for ya on that on

paulbfd · Post by **paulbfd** » Tue Aug 14, 2007 11:32 am

I'm just hoping it won't go all "Reference 500" on me and fill the car with orange smoke!

1moreamp · Post by **1moreamp** » Tue Aug 14, 2007 2:26 pm

Sounds like solder and caps time

paulbfd · Post by **paulbfd** » Tue Aug 14, 2007 8:52 pm

Could you go into a little more detail please?

The fella I got it from has a load of spare PG caps he says I can have for free.

If I whip the lid off, is there something visible I can check for (like anything loose)?

1moreamp · Post by **1moreamp** » Thu Aug 16, 2007 1:58 pm

paulbfd wrote:Could you go into a little more detail please?

The fella I got it from has a load of spare PG caps he says I can have for free.

If I whip the lid off, is there something visible I can check for (like anything loose)?

Look for bad solder on the A1360 and C3423 transistors in each channel, then look for bad solder in the 16 volt zener diode area of the power supply. Then for general principals replace all the 12 volt side 2200 ufd caps.

Is that enough info? ??? C

PS If your having trouble following those instructions then your probably not experienced enough to be inside the amp doing this sort of work anyway. Nothing personal against you but this stuff takes practice and time and some basic Electronics education to be performed properly. So don't be hurt by my comments, i am just trying to help you to help yourself and to prevent damage to your property also.

paulbfd · Post by **paulbfd** » Thu Aug 16, 2007 9:06 pm

1moreamp wrote:don't be hurt by my comments

Not at all Cecil, your input is greatly appreciated.

I'll be the first to admit I haven't got a clue what going on inside an amp

Having spoken to the UK's chosen PG amp repairer (Base Systems) they're were unsure what could be causing the problem also. I thought if there was a chance something visible would give it away then I'd know what I was up against.

1moreamp · Post by **1moreamp** » Thu Aug 16, 2007 9:56 pm

PM sent, C

paulbfd · Post by **paulbfd** » Mon Aug 27, 2007 4:47 am

Finally got the lid of this thing to have a look.

Topside everything looks fine from what I can tell (which doesn't mean much!), nothing discoloured, no signs of cap leakage.

Underneath though, there were a few areas of brown at solder points, here are some piss poor camera phone pictures that might give you some idea:

Could this be the route of my crackling issue?

Many thanks

marko · Post by **marko** » Mon Aug 27, 2007 5:18 am

don't think so, looks pretty normal to me..

1moreamp · Post by **1moreamp** » Mon Aug 27, 2007 9:44 am

Those look to be flux contaminated, and those are in the power supply area of the amp. The bad solders i was thinking of will be located in each of the channels, and they will be the first big transistors in each channel on the board as you scan from the front to the rear of the main board area...

paulbfd · Post by **paulbfd** » Tue Aug 28, 2007 10:11 am

I can't say as I saw anything untoward. Will have another look again and report back later.

1moreamp · Post by **1moreamp** » Tue Aug 28, 2007 10:14 am

Look for broken solder joints on the RCAs. They will appear as circles in the solder surrounding the post of the RCA stem connections. If you wiggle the connector you will see the stem move back and borth. This is something you won't see if the solder is good...C

HoseHead · Post by **HoseHead** » Tue Aug 28, 2007 11:40 am

And buy a new camera...