Sony SL-HF100- Switched mode power supply diagnostics - UK Vintage Radio Repair and Restoration Discussion Forum

monaro0162 · 6th Jun 2022, 6:31 pm

Hi everyone,

Acquired this a while ago, was completely dead on arrival.
On inspection the power supply was found to be physically damaged - cracked pcb and tracks around the central transformer.
I fixed all the broken tracks using braid and solder, checked all the transformer and inductor windings, checked all the capacitors/diodes and transistors, replaced the capacitors in the secondary cct, the power supply seems to be 'trying' to power up as the clock is now functional, as you press the on button the relay vibrates for a moment, and the display changes to 'AU' but the machine does nothing else. The clock display dims a bit when the relay vibrates.

On the PAL site there is a mention of exactly this scenario I checked the transistor quoted but it tests out fine.

A check of the voltages on the connectors on the power supply reveals the following:

CN001 - nothing.
CN004 - nothing
CN002 - nothing
CN007 - 12.2v present but no 9v (0)
CN005 - 12.2v present 6.2v present
CN003 - minus 30v present, 40v present.
CN006 - nothing.

Could anybody help with finding out why the machine does not power up?

G6ONEDave · 7th Jun 2022, 3:30 pm

Might be worth checking D628, R629, D629 and the associated circuitry involved with the 12v supply.

Dave

HamishBoxer · 7th Jun 2022, 6:54 pm

Is it AU or AV, audio visual input?

patrickgnl · 7th Jun 2022, 7:11 pm

Quote:

Originally Posted by HamishBoxer

Is it AU or AV, audio visual input?

I had a SL-C30 - back in the day - that had the same display, but instead of +/- channel selection there was 1-12. AU definitely means auxiliary input, which was selected via a slide switch on the front I think. The video in and out were via BNC connectors.

But….. from the post it sounds like the problem is more fundamental than that..

Patrick

monaro0162 · 7th Jun 2022, 7:48 pm

I have the cct diagram now, by what voltages are present and not present, it would seem that there is something wrong around the circuit that activates the relay.

If I power the PSU up with only CN5 connected, so as the on off button on the fp is connected, the relay clicks but then clicks out and doesn't stay in, before it made a buzzing noise with all the connectors connected. Lack of switched 12v (&9v) seems to be the main issue.

I can't find any failed components in that area, so next I'll have to get the meter and scope out

monaro0162 · 7th Jun 2022, 8:57 pm

The power supply is actually working now - getting all the correct voltages and the relay is holding in - but this is with only CN5 connected. If I plug all the connectors in, no 9 & 12v, the relay buzzes but does not hold in. It's CN004 to the main board that's causing the problem, with this out voltages are normal with it connected the relay buzzes briefly then no 9 or 12v. So, aside from the broken PSU, it looks like it has a main board problem as well. I think that the AU is lit because it's part of the clock display and runs on the unswitched 12v line. Probably just stuck on AU because it hasn't been told to do anything else!

6th Jun 2022, 6:31 pm	#1
monaro0162 Pentode Join Date: Sep 2016 Location: Stansted, Essex, UK. Posts: 186	Sony SL-HF100- Switched mode power supply diagnostics Hi everyone, Acquired this a while ago, was completely dead on arrival. On inspection the power supply was found to be physically damaged - cracked pcb and tracks around the central transformer. I fixed all the broken tracks using braid and solder, checked all the transformer and inductor windings, checked all the capacitors/diodes and transistors, replaced the capacitors in the secondary cct, the power supply seems to be 'trying' to power up as the clock is now functional, as you press the on button the relay vibrates for a moment, and the display changes to 'AU' but the machine does nothing else. The clock display dims a bit when the relay vibrates. On the PAL site there is a mention of exactly this scenario I checked the transistor quoted but it tests out fine. A check of the voltages on the connectors on the power supply reveals the following: CN001 - nothing. CN004 - nothing CN002 - nothing CN007 - 12.2v present but no 9v (0) CN005 - 12.2v present 6.2v present CN003 - minus 30v present, 40v present. CN006 - nothing. Could anybody help with finding out why the machine does not power up? Attached Thumbnails

7th Jun 2022, 3:30 pm	#2
G6ONEDave Octode Join Date: Dec 2019 Location: Owston Ferry, North Lincolnshire, UK. Posts: 1,704	Re: Sony SL-HF100- Switched mode power supply diagnostics Might be worth checking D628, R629, D629 and the associated circuitry involved with the 12v supply. Dave __________________ Quote "All is hyperthetical, until it isn't!" (President Laura Roslin, Battlestar Galactica)

7th Jun 2022, 6:54 pm	#3
HamishBoxer Dekatron Join Date: Aug 2007 Location: W.Butterwick, near Doncaster UK. Posts: 8,935	Re: Sony SL-HF100- Switched mode power supply diagnostics Is it AU or AV, audio visual input? __________________ G8JET BVWS Archivist and Member V.M.A.R.S

7th Jun 2022, 7:48 pm	#5
monaro0162 Pentode Join Date: Sep 2016 Location: Stansted, Essex, UK. Posts: 186	Re: Sony SL-HF100- Switched mode power supply diagnostics I have the cct diagram now, by what voltages are present and not present, it would seem that there is something wrong around the circuit that activates the relay. If I power the PSU up with only CN5 connected, so as the on off button on the fp is connected, the relay clicks but then clicks out and doesn't stay in, before it made a buzzing noise with all the connectors connected. Lack of switched 12v (&9v) seems to be the main issue. I can't find any failed components in that area, so next I'll have to get the meter and scope out Attached Thumbnails

7th Jun 2022, 8:57 pm	#6
monaro0162 Pentode Join Date: Sep 2016 Location: Stansted, Essex, UK. Posts: 186	Re: Sony SL-HF100- Switched mode power supply diagnostics The power supply is actually working now - getting all the correct voltages and the relay is holding in - but this is with only CN5 connected. If I plug all the connectors in, no 9 & 12v, the relay buzzes but does not hold in. It's CN004 to the main board that's causing the problem, with this out voltages are normal with it connected the relay buzzes briefly then no 9 or 12v. So, aside from the broken PSU, it looks like it has a main board problem as well. I think that the AU is lit because it's part of the clock display and runs on the unswitched 12v line. Probably just stuck on AU because it hasn't been told to do anything else!