I'm french (sorry for my english 😉 an this helped me for repairing my DY294 tester.

The C9013 was cuted and the cummutator's pictures will helped me very much to replace the littles springs.

Thank you very much and have a nice day

Gregory.

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It seems that this is the case:
The 79xx voltage regulators series made by ST have to be connected to a load consuming at least 5 mA. Otherwise, their input voltage (decreased by about 8V) appears right at the output. So, according to our measuremets, you can get up to 20V at the output of a L7905 without a load.

Hope this helps?

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Sorry for my late response Riaan. I only saw your your additional question today.
It could be as easy as fixing the metal connectors/clips
inside that do not grip the Regulator Pins enough?
I take it that you are sure that your Regulators are not
Bad themselfs?
I tested a KIA7824 Regulator and measured the voltages
with my Digital Meter on all the pins marked 1 to 3 on the
Front of the DY294. Being pin 1 the Input of the Regulator.
Pin 2 the Ground and Pin3 the regulated Output. Between Pin
1 and 2 I measured 31.2V DC going in. And between Pins 3
and Pin 2 I measured 24.1V DC. Of course with the Selector
in position 78xx.
I hope this helps fixing your DY294?
Else your Selector Dial could also be wrong and my Repair article will be a great Service Manual that will help in checking all correct contact positions. And the schematic
should in addition give you all necessary details about the
used Components in the DY294 circuit. Good luck!

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Hi Albert.
Thanks for the reply. Tried it with different regulators. All measure wrong. What could be the problem in my meter? Would like to fix it.

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I looked on the internet for the Hakko you mentioned Robert. It seems very affordable. I myself already own the old but very good Ersa MS6000 I mentioned in the article which only has one or two long life Ersa Tip(s) that help me out whenever I have to solder the almost impossible repair tasks. And the Ersa also takes only a few minutes to warm up. (Up to 450 degrees Clesius - And has a [simple LM339?] protective startup circuit that prevents the Heater Element at cold - low resistance/high currents - startups). And I also got 2 Hot Air Solder Stations with integrated SMD solder irons. So I'm happy with these for now. I also recently bought the very affordable S-993A Desolder Pistol as mentioned in my article. Like your Hakko Desolder Pistol. See:

http://nl.aliexpress.com/item/Free-shipping-by-DHL-S-993A-Electric-Vacuum-Desoldering-Pump-Solder-Sucker-Gun-220V-90W-Upgrade/32432070015.html

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That's true Albert. We are all limited by our tools, equipment, and knowledge. I replaced a USB-B micro 5 pin charge plug dock in a Kindle device and realized I was severely limited by my cheaper Weller soldering iron and it's poor choice for tips. I bought a new Hakko FX-888D-29BY a couple of weeks ago that is much better and has many nice tips to choose from. I'll be able to do much better soldering now.

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I know what you mean Robert. But connecting any QFP-44 chip is just hard because I do not have a test socket for them. At least not in the QFP SMD type of chip. I don't even know if they exist.

Testing these 'ICL' compatible 7106 types is only easy if you know how to solder these very tiny pins with very small spaces between them.

You only have to check if the chip oscillates when you hook a Resistor (100K) and Capacitor (100pF) to Osc 1 to 3. And about 9V dc to the V+ and V- pins like I mentioned in the article.

I never expected to find 4 (!!) AME 7106 QFP-44 chips that were garbage. I thought I did something wrong but I didn't because my first CS7106GN chip tested functioned straight away. And it was no ESD problem either because both my DIP AME7106's worked from the start too.
Which rules out ESD failures, and as you say kind of proofs that they must have been Fake (or defect) from the start.

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