Bench PSU problem

A problem with my bench power supply, constant current mode won't keep it's setting and just leask back to zero.

Category:

Entertainment

Tags:

• constant
• current
• mode
• problem
• bench
• psu
• power
• supply
• electronics
• panasonic
• sd20
• Power Supply

[Alex1M6]

Did you ever find out what was causing it to do this?

[orbiter8]

@Alex1M6 I didn't I'm afraid. I had a few ideas and suggestion given on the eevblog, however I needed a PSU that was 100% functional & trustworthy, so I ended up spending the cash & buying a new TTi QL355T which is a fantastic PSU. The Circuit Specialists PSU is just used as a back-up now should I ever need one.

I do know of a few other folk who've had the exact same problem as me with their Circuit Specialist PSU's so obviously it's a common issue with them.

Regards

John

[Alex1M6]

@orbiter8 Ah ok, perhaps if it happens with other PSU's of the same brand it might be some fault with an IC not retaining its values on the 2nd channel/supply rail. Although I am no expert when it comes to micro-controllers (More of a high power destruction person me lol).

[orbiter8]

@Alex1M6 It could be mate. It was strange though how the initial setting just drifted away though. It was similar to the sort of thing you'd see if you connected a capacitor up to a small load, and watched the voltage drain away.

Yea I've seen the sparks flying around on your vids :) Keep it up ;)

John

[vegmatic1966]

Have you checked for bad capacitors? This can affect both linear and logic circuits causing odd behavior or complete malfunction. Nice power supply, BTW.

[orbiter8]

@vegmatic1966 I didn't actually strip the thing apart my friend, but I will do at some stage. This PSU is actually sitting in the cupboard now even though it's almost brand new as I had the fortune to upgrade not long after I bought it, so I treated myself to a new TTi QL355T psu which is far better. Mind due it should be for the price :o

Regards

John

[orbiter8]

Hi mate, Hey don't worry.. the only stupid type of question is an un-asked question.

Yes, I'm affraid the PSU reacts the same way under all loads :( I have later found out that a few other people with the same PSU have either the same, or a very similar problem. I had a guy on the EEVBlog (Dave Jones electronics blog) who had a look at the circuit diagram, and between us we could quite trace where this problem may be originating.

Cheers

John

[wired2hack75]

I know this is a stupid question, but does it react this way no matter what the load?

I had this problem with a tv once, have you checked the momentary switch?

my tv always went to av input no matter what I set it on. ended up being a stuck

tactile switch. ps thanks for the sub.