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Author Topic: 32V-3 Audio Mod  (Read 3145 times)
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wa2fxm
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« on: October 29, 2017, 12:06:50 PM »

Greetings all. This is my first post on AMFone. Looks like a good place to ask some questions about the WA1HLR Audio Mod which I am attempting to install in a 32V-3. I've clipped out and replaced the 8 capacitors and 1 resistor with the new higher value components. But I find that after all that clipping I've got what appears to be a dangling resistor pair.

When I first opened the unit up I saw that someone along the way had added a 50uF capacitor between pin3 of the 6SL7 and the junction of R211 and R210 which is supposed to be chassis ground. The 2 resistors and a 3rd black wire which disappears back into the chassis wiring harness are sitting on a terminal strip and I'm measuring 2k ohms there not ground. None of this is showing up on any schematics or pictures that I've seen in the manuals. Searching the forums here looks like there's some pretty good 32V experience amongst you. Anyone have any idea what's going on here?



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KL7OF
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« Reply #1 on: October 30, 2017, 08:22:08 AM »

I did the Wa1hlr audio mods to my 32v1 many years ago...There were a couple mistakes in the schematic...I talked to Tim about it and he said that there were indeed mistakes....Now that being said, I can't remember what the fixes were, but they were simple and minor....I do remember having to play with the values of the coupling cap and resistor in the neg feedback circuit to get the proper amount of feedback....Good Luck and maybe Tim will chime in and show us the way...I still have that radio and should put it back on the air...  Steve
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wa2fxm
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« Reply #2 on: November 13, 2017, 11:41:37 AM »

I've got the audio compartment pulled apart and I'm finding a lot of non-schematic stuff. Besides the aforementioned 50uF capacitor there's a small mica capacitor on pin 1 of the Mic connector to ground. The black wire at the junction of R211 and R210 goes back directly to the -75V Bias supply. So instead of being tied to ground the two resistors are tied to the -75V supply. I'll be weeding this all out to get it back to original, but the next time someone has their 32V opened up if you could take a picture of your audio compartment and post it here I'd appreciate it. I'd like to try and figure out what someone had in mind when they got into this thing. Thanks.

Mark - WA2FXM
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KL7OF
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« Reply #3 on: November 13, 2017, 02:45:32 PM »

There are a couple different schematic from the factory if I remember right...worth looking into...good luck..Steve
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Steve - K4HX
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« Reply #4 on: November 13, 2017, 03:30:19 PM »

I wouldn't bother trying to figure out what someone else did years ago. Set it back to stock and go from there.
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