Electronic Measurement INC - HCR 10 Series Schematic - Page 1
Forum section: electronics / repair

author: DrijSkij
author_rank: Contributor
timestamp: September 15, 2025, 01:44:22 pm
content: Hello. I'm not having any luck finding a schemetic specifically for an HCR series 0 - 150V 0-2 A power supply. If anyone would be kind enough to share it with me I would greatly appreciate it. I've search the web and have not found anything.Thank you.

author: Swake
author_rank: Frequent Contributor
timestamp: September 23, 2025, 09:10:44 am
content: This thing?

author: DrijSkij
author_rank: Contributor
timestamp: September 23, 2025, 01:01:13 pm
content: Yes. The 150 VDC 0-2A. Would you have a schematic for it?

author: DrijSkij
author_rank: Contributor
timestamp: September 23, 2025, 01:05:29 pm
content: I also own the 0-20V 0-13 A verson and I do have the schematic for it. However, the strategy and design is not at all similar to the 0 to150 V 0-2 A version.

author: Swake
author_rank: Frequent Contributor
timestamp: September 23, 2025, 01:46:15 pm
content: Well, for some reason I uploaded only one of both files. Hope this is the good one.Looks like both 150V and 20V are in there.

author: DrijSkij
author_rank: Contributor
timestamp: September 23, 2025, 06:23:47 pm
content: Thanks. However, I already have this for the 20V 13 Supply.

author: Swake
author_rank: Frequent Contributor
timestamp: September 23, 2025, 07:22:42 pm
content: The 150V/2A version is in the same document. Differences are some components changed and the presence or not of a OVP.But you write that it has a different design. What is the exact model number? (see sticker on the bottom, also has the serial).Could you please post a picture of the front, back, and an overview picture of the PCB with the Assembly ID marking readable.

author: DrijSkij
author_rank: Contributor
timestamp: September 24, 2025, 10:17:17 am
content: Hi again. Thanks for responding. I became familiar with the 0-20V 0-13A version of the power supply(because I own one) - schematically and the physical layout. When I opened up the 0-150V 0-2A version I immediately knew that it looked significantly different than the former that I had mentioned.I do know that the schematic does mentiion other similar versions of power supplies and the variatioins of the parts for each particular version. However, if you had the luxury(as I do) of having both versions of supplies in front of you , you would know immediately that they are significantly different in design, strategy , and layout.For example, the 0-13A version has a TRIAC front end for the large current requirements . The 0-2A version likely would not need that.So, I guess what I'm trying to say is if the schematic applies to both supplies as it you are assuming, then both should look overwhelmingly similar in physical layout and have many of the same parts and only the variations that the schematic lists.My only complaint about the 0-150V supply is that it has a bit a settling issue when you set the voltage around 25V. When you adjust the knob the voltage on the meter will hunt a bit, and then settle on the final value in a few seconds. I tried spraying the 10 turn pot with contact cleaner. Maybe I need to physically work the pot a bit more.I guess my task is to do some deeper analysis of the 150V version.

author: Swake
author_rank: Frequent Contributor
timestamp: September 24, 2025, 10:49:32 am
content: If the 150 V power supply has a different design then it is not a HCR 10 series model or someone with a Dr Frankenstein mind bodged something together in a HCR 10 box. That is why I asked for pics.To diagnose the issue you might temporarily add a resistor of about 2 kOhm/1W in series with the 10-turn pot. That will 'move' the 25 V section on the pot two turns away. If the voltage is stable now you know there is an issue with the pot and not with the circuit.

author: DrijSkij
author_rank: Contributor
timestamp: September 24, 2025, 11:17:53 am
content: Ok. I'll try to take some comparative photos. I'll try to get to it in a few days. Thank you.