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Montgomery Wards GEN 719A

TM86

TM86

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Jul 6, 2014
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Anyone with a copy of CB-292 care to look up the value of VR2? I think it's supposed to be 1 k OHM, but mine is broken and it's a bit difficult to get a good reading off what's left. Not my fault, opened the cover and one of the legs fell out.

PC-622 AA is the mainboard number, just in case someone knows of another radio that used the same board.
 

I had one of those... I recall it being pretty good.

I wish I still had it... but I got PO'd during a garage cleanout years ago and threw it out.
I used to be young and stupid... now I'm not young anymore!
 
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This one's a bit... different. Some previous owner didn't get it clear of their paint booth and so now it's got overspray on the mic, mic cable, knobs, and bottom. We'll see how it does after a recap and replacing that broken pot.

Meter may be stuck too, but I've got options there.
 
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Got the replacement for VR2 in today. Dropped right in, which was nice. Since the radio is electrically complete, minus any solder joints I may have missed, I decided to start playing.

Receive seems to work all modes, transmit not so much. Sideband is fine, but no output in AM.

I'm using the old (MB8719) McKinley schematic as a reference, because that's the closest I've got to the good stuff. Transistor and IC numbers all seem to be the same. Other components... might match.

I found TR35 was bad, replaced it. Doesn't seem to be shorted any more. Since it's in a Darlington pair config with TR34 I replaced that, too. But still no go. Voltage on the emitters of both transistors more or less drops to zero when the radio is keyed. Sounds like a short, and I would normally suspect the final or driver, but I'm getting around 12 watts in sideband.

So, yeah, I'm confused. Haven't given up just yet, though. Seems to be something only present in AM transmit, but that's about all I've got for the moment.
 
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I do not have the Sams, as that's CB-292 and my collection stops at 291. The MB8719 McKinley in Sams CB-219 is as close as I can get. The PLL section is different, but most of the components are physically in the same location otherwise. Traces on the board are laid out a little differently as well. So it's quite possible that that there's some little nuance that I'm not aware of.

Or it could just be that I'm flailing. Never leave that one off the list.
 
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Did a little more on this thing. Disconnected the wire that leads from the modulation transistor (TR 35) to the mode switch. Did not get the big voltage drop when keying the mic like before. Reconnected the wire. Pulled the next components in line which were the driver, final, and the AMC transistor. Putting them back one by one showed that the voltage at the collector of TR 35 didn't drop to zero unless the final was is inline.

Coincidentally, I lost sideband transmit as well. So I may have blown up my final or just pushed an iffy component to the breaking point.

I did check the final (2SC1969) on my little China built component tester. It recognizes it as a bipolar transistor, but says it has an Hfe of 8. Which seems a little low since minimum spec is 10.

So now I'm dithering over something I know I'm going to do at some point, ordering some HG 1969's. I've already got the ICA web site up in another tab, I just need to put in the number of them I want and pay. AT $3.65 a pop (as of today) it's not that expensive. If they're really in stock.
 
Got the HG 1969's and put one in. Sideband transmit is back!

AM, not so much. So, back where I started on that.
 
TM86 said:
Anyone with a copy of CB-292 care to look up the value of VR2? I think it's supposed to be 1 k OHM, but mine is broken and it's a bit difficult to get a good reading off what's left. Not my fault, opened the cover and one of the legs fell out.

PC-622 AA is the mainboard number, just in case someone knows of another radio that used the same board.
Click to expand...
Can anyone send me a picture of the Ward 719 and the 719A or tell me where to find pictures.. Thx. 73, W.G. Davis
 
I have one picture of the 719A. It is attached.
 

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  • Wards_719A.JPG
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