Schematic for a Tenma DC Power Supply 705-72

[James Silva]

I am searching for a legible schematic diagram for a Tenma 705-72 DC laboratory power supply. Each of its two channels uses a LM723 regulator and a pair of 2N3055 power transistors. One of the channels operates normally; the second channel puts out the maximum voltage (37 volts). Any help, particularly a schematic diagram, would be appreciated.

 

[Averagesupernova]

I would start with data sheets for the LM723 regulators. There is only so far the power supply design can get away from what is recommended in application data.

 

[Rive]

Adding to that, you have two almost identical channels to compare...

 

[Tom.G]

1. Inspect for burned parts; replace as needed.
2. Replace both the LM723 and the 2N3055. (they are cheap)

If the 2N3055 failed, it likely took the LM723 with it.

Cheers,
Tom

EDIT: I found one 5 year old reference that said they contacted MCM Electronics for a schematic and they sent him one! MCM is now owned by http://www.newark.com, which sells the Tenma product line.

 

[dlgoff]

... owned by http://www.newark.com

Nice. I use to do a lot of catalog ordering before there was an "internet".
... bookmarking