Repair procedure question

[mac dillard]

For you guys that repair amps like the Marshall TSL 2000 series, when you have to pull the main PCB what system do you use to keep up with which jumper goes to which location. I have been working on a Marshall TL60-60-02 and for the life of me I can't tell from the schematic where the jumpers actually go. You would think they would number them, maybe they do and I am just missing it. When I design my amp I'm going to do it so that you can get to the under side of the mother board without having to pull it. Just joking.

[drewl]

I write the number on the plug.
I've had to repair several due to the bad early PC boards becoming conductive, so alot of the connections are remembered bit its always good practice to write down the connections and connectors for anything you work on.

And the next time the same type of amp comes in you have that info.

[Jazz P Bass]

I draw the connections on a sheet of paper as I remove them.

Kind of like a crude layout diagram.

Nothing fancy.

From here to there is all I need to put it back.

Note: they are marked but on some schematics it does not match up with the actual silkscreening on the board.

[Tom Phillips]

I made a spread sheet matrix listing each cable's connection points.

[Steve A.]

I draw the connections on a sheet of paper as I remove them.

Kind of like a crude layout diagram.

Nothing fancy.

From here to there is all I need to put it back.

Note: they are marked but on some schematics it does not match up with the actual silkscreening on the board.

Gee whiz... perhaps someone someday will invent a telephone that we can actually put in our pocket and even use to take megapixel color photographs. Boy, wouldn't that be really neat!

[Sarcasm mode: OFF]

Seriously, hand drawings can contain information not obvious in photographs, which will let you know if everything looks normal after putting things back together.

For simpler circuits in music electronics or HVAC equipment I always keep a Sharpie in my pocket and use dots or hash marks to indicate where cables or plugs would go.

Steve Ahola

[nickb]

1) Take a photo - this is backup and helps with the lead (re-)dress
2) With a sharpie, write on the plug. If this gets rubbed off you still have the photo.

[Mick Bailey]

I use small masking-tape 'flags' on each cable and write the on the location with a Sharpie.

With complex/unfamiliar gear I take pics and make notes. Sometimes the routing is important, too. Also, where a connector is unpolarized/unkeyed and can be reversed, I mark a reference line on the connector as well as the board to make sure it goes back correctly. Sometimes it's important, sometimes not.

[mac dillard]

That is pretty much what I do Mick. I take pictures and mark each cable and connector with dots and masking tape flags which I number. I use to use the numbered stick on tags that you can buy books of. Would be nice if layout drawings were available. Some are but I haven't found any for the Marshalls. I was just thinking there has to be a easier way. Guess not.

[Enzo]

And don't forget the simplest: don;t disconnect in the first place. When I need to get under the board on a TSL or DSL or similar, I disconnect the wires along the rear wall, like the transformer connections to the speaker selector switch, maybe clip a wire tie to the little notch on the rear chassis wall. I might have to pull a couple PT wires. But all those little cables to the front panel boards, I leave in place. The amp is sitting knobs towards me with the open side up, so speaker jacks facing away. I can usually flip the main board over towards me, exposing the underside.

My chassis usually starts out parallel the bench, but if I need a better angle on the board, I can tip it towards me so the front of the chassis is on the bench and the amp slopes at 45 degrees up away from me.

I agree with all the above ideas though, as I ALWAYS make a chart or diagram and/or label wires when I disconnect.

I would take photos too, but I don;t have a camera, and I don;t even carry a cell phone. Photos are great, but you need to be sure they are clear. Some nice photos we see here have a wire hiding under some other wire.

[gbono]

I use the attached for the TSL 100..........

[Steve A.]

I use the attached for the TSL 100..........

Let me get my magnifying glass out...



Looks really nice!

Steve Ahola

[blindboybenton]

Well i just last week had to removed a board from a valve hifi amp with SS pi stage that sit vertically with a chassis back piece covering half the board

Drawn everything out pictures of everything. then discounted everything ( all soldered ) run extension wires so i could work on the amp and get to everything i wanted. was a nightmare
BBB