Help with CLEAN

[BigBrewtus]

I just bought and recieved a used CLEAN module. I knew it had problems before I bought, so no big deal. I think I would like to fix it if I could. I got a new soldering iron too. The module was cheap enough that if I really screw it up I wont feel too bad. :lol:
The module cuts in and out with any movement of controls. When you do get full volume it sounds really raspy and not in a good way. Looking over the module there is one resistor that doesnt look like it has a good solder on either end. Let me know what you think.

 

[HughJasol]

The pads of R1 do look discolored as if they had been hit with an iron already. If R1 looks like that on the underside then I would definitely start there. If it looks clean like the other components then it's probably not causing you any problem, as these are not multi-layer boards AFAIK. But I'd probably hit that mess with the iron anyway . . .

 

[HughJasol]

Also: Did you clean the tube sockets, and also check that none of the holes are too loose and not making good contact with the tube pins?

 

[BigBrewtus]

That resistor looks pretty clean underneath. Didnt clean the sockets yet but did put new tubes in to make sure of a bad tube.

 

[ibenhad]

Did you try cleaning the main connector pins? Have you ever sprayed the female connector socket in the amp with some deoxit or at least some contact cleaner? That board doesn't look to healthy @ R1 I would remove and replace the resistor. They cost next to nothing and I wouldn't trust the one that's in there. Post a pic of the entire board including tube riser board.

 

[SacredGroove]

The resistor looks OK, but replacing it isn't a bad idea. It was probably a 470ohm originally and swapped out for the 150ohm in there now. While changing it, the top solder pads were probably heated right off the board. As mentioned in an earlier post, if the connections look good on the bottom then it should be fine. :wink:

For the sound cutting in/out, check continuity between ground terminals on the gain, mids, and level pots to the board, or between the pots themselves (gain ground to mids ground, etc...). When looking at the module, the ground terminals are on the left of each pot listed above.

Post back about what you find. 8)

 

[kc2eeb]

I'm an IPC-A-610 IPC Specialist. That resistor looks pretty crappy.
The boards used in the MTS series are plated through so, a good solder joint needs to be properly done through the hole. It's got to be good top and bottom.

 

[BigBrewtus]

Okay, I tore it apart and posted more pictures. I dont see any problems. Havent hooked up the fluke meter on it yet. Bare with me. This is the first time messing with stuff like this. :? I have worked on cars and baised amps but not this. What grounding points should I use when checking the points suggested, Mr. SG? :wink:

 

[RADE01]

I'm an IPC-A-610 IPC Specialist. That resistor looks pretty crappy.

Excuse my ignorance, but what does that code mean? :?

 

[Jaded Faith]

Don't rule out the possibility of a broken pot, particularly with the original symptoms you described.

 

[BigBrewtus]

Knobs were broken on the GAIN and BASS pots. Everything PHYSICALLY appears fine. AKA no excessive movement of shaft on pots. How else would I check them?

 

[SacredGroove]

What grounding points should I use when checking the points suggested, Mr. SG? :wink:

Looking at the module from overhead, go to the rear connector and count three rectangle pads from the left, and you will get a group of three pads that are ground. You can use one of those as reference. You can put one lead of the meter on any of those tabs and the other lead on the terminals I mentioned in my previous post.

When placing the lead on the pot, put it in the circular terminal and slightly wiggle the pot. You should get a good reading even after wiggling the pot. If the connection cuts out at any point, then you can melt some solder on the back of the terminal where it meets the board.

Do this with at least the gain and volume pots.

Hope this helps!

 

[kc2eeb]

I'm certified to solder and assemble Class 3 mil spec electronic equipment. I work for an aerospace contractor for civilian and military
flight certified products. Every time you fly, most everything you see on a plane that blinks, glows, lights the runway or the wing tips probably came from the company I work for.
IPC-A-610 is an international standard for the quality of electronic assembly.
Class 3 is a standard where the component is expected to work without failure for it's entire service life.
Many consumer products are Class 1 which means it's only expected to work when it's manufactured.