Something a bit different to my usual..

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rubber_jonnie
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Something a bit different to my usual..

Post by rubber_jonnie »

Next on the bench for me is something I have been meaning to look at for a while, as it seems like a possible easy fix.

It's a 40 channel CB transceiver.

PXL_20220623_150343587.jpg
PXL_20220623_150343587.jpg (367.05 KiB) Viewed 261 times
PXL_20220623_150405487.jpg
PXL_20220623_150405487.jpg (372.8 KiB) Viewed 261 times

The main problem is that it doesn't run at all off batteries, but it does work off a 12V PSU. Hooking up a PSU to the battery connectors, and I see that the power does reach the board, but it doesn't switch on.

So deeper dive needed to see why we aren't powering up from batteries, as it's kind of not portable if you have to use a PSU to get it going!!

It looks like somebody has previously attempted repairs, as there is some sketchy looking soldering inside.

I'll give it a damn good clean whilst it's apart too.
Collector of many retro things!
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stephen_usher
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Re: Something a bit different to my usual..

Post by stephen_usher »

Eek! Analogue stuff! :-)
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
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rubber_jonnie
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Re: Something a bit different to my usual..

Post by rubber_jonnie »

stephen_usher wrote: Thu Jun 23, 2022 4:38 pm Eek! Analogue stuff! :-)
Very much so, and I haven't found (And doubt I will) a schematic yet!
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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PhilC
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Re: Something a bit different to my usual..

Post by PhilC »

Another interesting project, probably a diode that’s supposed to block the psu input from the batteries would be my guess?
If it ain't broke, test it to Destruction.
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mrbombermillzy
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Re: Something a bit different to my usual..

Post by mrbombermillzy »

From the little I can see of the battery terminal springs, they look like they've had a touch of the battery rot. I can see bright green!

Are you sure it's not those? (Perhaps you are connecting the PSU on a better/conductive part of the metal?)

Besides, it must be worth a try... you must be getting withdrawal symptoms re: repairing battery damage by now, surely? :lol:
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rubber_jonnie
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Re: Something a bit different to my usual..

Post by rubber_jonnie »

PhilC wrote: Thu Jun 23, 2022 7:02 pm Another interesting project, probably a diode that’s supposed to block the psu input from the batteries would be my guess?
Yeah, a diode was on my list too, and there is one, but there is also a charge port and I'm wondering if there is an issue in the charge circuit, so again, diode or other component
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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Re: Something a bit different to my usual..

Post by stephen_usher »

Maybe the charge input jack disconnects the battery and the contact in that switch has corroded?
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
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rubber_jonnie
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Re: Something a bit different to my usual..

Post by rubber_jonnie »

stephen_usher wrote: Thu Jun 23, 2022 8:31 pm Maybe the charge input jack disconnects the battery and the contact in that switch has corroded?
That's a good thought, I'll take a look thanks.
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
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rubber_jonnie
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Re: Something a bit different to my usual..

Post by rubber_jonnie »

Ok, so the lack of any sort of schematic has really been a huge pain, however looking closely under a bright light I noticed that there was a diode and capacitor that were installed in the wrong slots, so diode where the cap should be and vice versa:

PXL_20220629_185027882.jpg
PXL_20220629_185027882.jpg (243.36 KiB) Viewed 81 times

It looked very like it was that way from the factory, so I'm now wondering if it ever worked.

So after switching I had battery operation but then the mains adaptor no longer worked. The long and short of that was a broken, now fixed trace.

Here it is in all its glory:

PXL_20220629_214955852.jpg
PXL_20220629_214955852.jpg (276.45 KiB) Viewed 81 times

And it now happily runs off either battery or mains adaptor, or a 12v adaptor if in a car. I can't find a suitable barrel jack in my spares to test charging, and TBH I'm not too worried about using rechargeable batteries in it.

I think I may get my original Xbox on the bench next, as I hear the supercapacitor used for the clock circuit has a habit of leaking, and I really don't want to have to repair that!!
Collector of many retro things!
800XL and 65XE both with Ultimate1MB,VBXL/XE & PokeyMax, SIDE3, SDrive Max, 2x 1010 cassette, 2x 1050 one with Happy mod, 3x 2600 Jr, 7800 and Lynx II
Approx 20 STs, including a 520 STM, 520 STFMs, 3x Mega ST, MSTE & 2x 32 Mhz boosted STEs
Plus the rest, totalling around 50 machines including a QL, 3x BBC Model B, Electron, Spectrums, ZX81 etc...
Tomswork
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Re: Something a bit different to my usual..

Post by Tomswork »

Nice repair. I will turn my old cb on to c19 and listen. And I may need to adjust my flux capacitor 1971

Tom
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