Altec 1592B Mixer Amplifier Rebuild, Pt. 3: Tone Control Board

Last time around we removed the Tone Control board from the front panel of the Altec 1592B.

You can see there are 2 pots - for the LF and HF controls - that are soldered right to the board.

I need to remove them in order to get to the resistors underneath.

A little solder wick and poof! the LF control is removed.

Now we can clearly see the resistors under it. There's also more room to get at the electrolytic caps and other resistors I'm going to change out.

Half the board is done. I'm leaving the original plastic caps. For one thing, they're probably not leaky. And for another, I don't have the right values on hand - most of mine are either too low voltage rating for this circuit (as in 50 volts or less) or too large to fit high voltage (630 volts or so).

I don't think the universe will end if I leave them in. Unlike the electrolytics, which will become the undead electrolytics and eat the brains of whatever they're installed in.

I wanted to clean the pots while I had the whole thing apart.  I have been known to open them up to give them a proper cleaning.

In this case, I was lazy and I figured I'd just see if I couldn't get a few drops of contact cleaner in them.

Instead of spraying cleaner "into" the pot, (which means the spray goes everywhere except into the opening in the pot), I sprayed some cleaner into a cup.

Then I sucked some up into the fantabulous Stew-Mac pipettes I keep on hand.

And drip, drip, drip into the pot.

Here's the board almost ready to go. Just need to put the HF control back on.

Next time: the filter caps on the main chassis.

Altec 1592B Rebuild Project
Part 1: Overview and Initial Dissassembly
Part 2: Power Amplifier/Main Board
Part 3: Tone Control Board (This page)
Part 4: Filter Capacitor Replacement
Part 5: Reassembly