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Forum 135

Test Equipment Altai PP-245

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arelectrical
(@arelectrical)
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Does anyone have a diagram for this regulated power supply I believe it’s based on the LM723 & 2N3055 transistors the IC is missing & various cables are cut removed , Electrovision no longer have any service info on this model or any from this period. Any help appreciated 

 
Posted : 06/10/2024 4:23 pm
Michael Dranfield
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Didn't all CB power supplies run on the same chip and transistor. 

 
Posted : 06/10/2024 4:37 pm
Cathovisor
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You could likely work it out from the datasheet for the 723, which I seem to recall had a diagram for just such a supply.

 
Posted : 06/10/2024 5:09 pm
crustytv
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I have the ALTAI PP-243, does this look similar?

alt1
alt2
alt3
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alt5

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Posted : 06/10/2024 6:43 pm
Cathovisor
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Similar, but not the same Chris - the OP's would be a 5A unit, here's an example:

https://www.ppauctions.com/archived-lots/109917/lot-532/altai-pp245-psu-0-24v-5a-t124-lot-located-a

Yours seems to use (possibly) a dual op-amp for the error amplifier.

 
Posted : 06/10/2024 7:02 pm
arelectrical
(@arelectrical)
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@crustytv Hello thank you for taking the time to photograph the inside of your power supply. From the outside the unit is identical but mine has a vertical PCB with a larger IC which I’m assuming is the LM723 . In your workshop I noticed you have a little Eagle PSU this uses the same IC & a diagram would be handy if you have one. I’ve got various LM723 diagrams from google but they seem to differ on the pin connections hence why a diagram for the PP-245 would confirm the IC type.

 
Posted : 07/10/2024 6:04 am
crustytv
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Posted by: @arelectrical

In your workshop I noticed you have a little Eagle PSU this uses the same IC & a diagram would be handy if you have one.

Hi you'll have to forgive me, but I have no idea what you mean "Eagle PSU", I have just two PSU's (see below) one linear, the other SMPS. Can you point me to the photo you've looked at? The only other PSU I had was a Philips, which I passed on to another member a good few years ago.

20241007 071629

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Posted : 07/10/2024 6:22 am
Cathovisor
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@arelectrical LM723 pinouts naturally vary between the plastic DIP version, the metal can version which has fewer leads and the surface mount version. Get the datasheet direct from TI and if it is a 723, you can work it out from that but frankly, if the PSU has been butchered in the manner you describe I'd bin it and look for something like a Farnell L30/5 to replace it.

 
Posted : 07/10/2024 8:28 am
arelectrical
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@crustytv 

Hello it’s to the left on the very last picture in the 1970s TV shop museam 

 
Posted : 07/10/2024 4:43 pm
arelectrical
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@cathovisor Hello yes indeed I have a Farnell L30.  This Altai  power supply is just a project which I’m hoping I can get to the bottom of

 
Posted : 07/10/2024 4:45 pm
arelectrical
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@cathovisor yes it dos use a dual op amp with a reference voltage of 7v

 
Posted : 07/10/2024 4:51 pm
Cathovisor
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Posted by: @arelectrical

@crustytv 

Hello it’s to the left on the very last picture in the 1970s TV shop museam 

Do you mean this?

Screenshot 2024 10 07 at 20 03 11 CrustyTV Vintage Television Museum

 

 
Posted : 07/10/2024 7:05 pm
crustytv
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That's the Altai PP-243, as shown in post #4 above, when it used to live on the store room test bench.

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Posted : 07/10/2024 7:17 pm
arelectrical
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@cathovisor Yes that’s the one. It uses the LM723 the same as the PS I’m working on

 
Posted : 08/10/2024 4:41 am
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