Power supply identification needed

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Buick Mackane
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Re: Power supply identification needed

Post by Buick Mackane »

Transwarp wrote: 12 Nov 2021, 21:02
Buick Mackane wrote: 12 Nov 2021, 20:00 Best CB power packs were ''mr whoosh power houses'' Blue cases. And a picture of mr whoosh himself scribbled on the front panel..You just don't see quality like that anymore
My disgusting pic for tomorrow on the 'Where's Weety ?' topic. :thumbup:
Nice one, Not seen one of those in yonks :thumbup:
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Re: Power supply identification needed

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Mudslinger wrote: 12 Nov 2021, 20:59 That was what i was thinking after doing a bit of internet "resurch". I am wondering of a cap has gone bad and caused the regulator to fail.

The regulator main parts seem to be a pair of transistors. One Large TO-3 type which has the part number BDW21 and is located on the heatsink, and another smaller TO-220 packaged device on the PCB which I am unable to read the numbers on until I remove it.
Could be aye. I'm not all that familiar with PSU's, Don't work on them, But is the big heat sink fella not a pass transistor and the other the regulator ?

Wheres sureshot when you need him lol.
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Re: Power supply identification needed

Post by ChubbyChops »

Mudslinger wrote: 12 Nov 2021, 20:19 When I said there was no output I appear to have a dodgy meter lead. It is actually putting out 24v

The output from the transformer inside is 36v (RMS)

I have some new caps which I will put in tomorrow.
Could have been modded for 24v hence why the writing on the front has been scratched off.
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Buick Mackane
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Re: Power supply identification needed

Post by Buick Mackane »

ChubbyChops wrote: 12 Nov 2021, 21:16
Mudslinger wrote: 12 Nov 2021, 20:19 When I said there was no output I appear to have a dodgy meter lead. It is actually putting out 24v

The output from the transformer inside is 36v (RMS)

I have some new caps which I will put in tomorrow.
Could have been modded for 24v hence why the writing on the front has been scratched off.
But the voltage rating hasn't
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Re: Power supply identification needed

Post by Transwarp »

Buick Mackane wrote: 12 Nov 2021, 21:06
Transwarp wrote: 12 Nov 2021, 21:02
Buick Mackane wrote: 12 Nov 2021, 20:00 Best CB power packs were ''mr whoosh power houses'' Blue cases. And a picture of mr whoosh himself scribbled on the front panel..You just don't see quality like that anymore
My disgusting pic for tomorrow on the 'Where's Weety ?' topic. :thumbup:
Nice one, Not seen one of those in yonks :thumbup:
Have a look again sir, it was less than 12 months ago since your last time ;)
www.transmission1.net/viewtopic.php?f=2 ... 14#p536014
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Buick Mackane
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Re: Power supply identification needed

Post by Buick Mackane »

i'd be investigating the over voltage before worrying about new caps, Just as well you never wired it to yer NOS Cobra to try it out :shock:
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Re: Power supply identification needed

Post by 14CS06 »

Hello

Schematic PP-1206G

BDW21 , Si, NPN, 90, 45, 5, 15, 200, 15, TO3.

2N3055 , Si, NPN, 117, 70, 7, 15, 200, 20, TO3

@+
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Buick Mackane
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Re: Power supply identification needed

Post by Buick Mackane »

Transwarp wrote: 12 Nov 2021, 21:19
Buick Mackane wrote: 12 Nov 2021, 21:06
Transwarp wrote: 12 Nov 2021, 21:02

My disgusting pic for tomorrow on the 'Where's Weety ?' topic. :thumbup:
Nice one, Not seen one of those in yonks :thumbup:
Have a look again sir, it was less than 12 months ago since your last time ;)
www.transmission1.net/viewtopic.php?f=2 ... 14#p536014
Yeah i did recall something quite recently about them being mentioned in another thread,


Well the schematic isn't a brain drainer....
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Re: Power supply identification needed

Post by Mudslinger »

Well according to the schematic the BDW21 is wrong, and it should be a 2N3055 (I have a new one here in my drawer) but isn't the voltage level set by the Zener diode?

To be honest there doesn't look to be much in there which could be wrong.
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Buick Mackane
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Re: Power supply identification needed

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Mudslinger wrote: 12 Nov 2021, 21:52 isn't the voltage level set by the Zener diode?

The zener regulates the base current on the transistor,

Its a text book PSU Schematic, Yea the bare minimum of parts, No OV protection
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Re: Power supply identification needed

Post by ch25 »

Trash it.
This PS is crap by design.
Power transistor going south, full rectifier voltage goes to the radio. Poof, magic smoke, precious equipment is dead.
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Buick Mackane
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Re: Power supply identification needed

Post by Buick Mackane »

You might want to consider knocking one of these up to protect your gear from future PSU Failures


https://www.electronicshub.org/crowbar-circuit/
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Re: Power supply identification needed

Post by The Collector »

Perhaps still use the suppliy's casing, but fit better/safer/more reliable components inside it?
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Buick Mackane
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Re: Power supply identification needed

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Be dandy with a simple mod or two
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Re: Power supply identification needed

Post by Buick Mackane »

This thread needs retitled and moved to the repair forum
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