UK 1400 PSU Recall

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I see some posts dotted around various pages about the recall of certain PSUs.

My question is does anyone have information of the differences between a pre and post recall PSU, and if so are the differences something that can be implemented if they are missing?

Thanks

H

[hellraiseruk]

There's not much to fix, only a transformer, rectifier Bridge and a smoothing capacitor, so I'd be interested myself

JD

[1024MAK]

Keep in mind that Sinclair did not make the PSUs, they contracted the manufacture out to other companies. Hence there at least three or more different styles (they all look the same on the outside as they all used the same case).

I don't know which were affected, or what the fix was (I suspect the recalled PSU were disposed of and Sinclair just sent out a replacement that did not have the problem).

Possible problems may have been:

• Cable clamp/grip not effective,
• No thermal fuse, wrong rating or not wired correctly,
• PCB tracks for the mains not sufficiently clear (clearance distance) from the low voltage output side PCB tracks,
• Transformer problem,
• Incorrect rated diodes,
• PCB or PCB mounted transformer able to break or come loose.

Or something else I can't think of...

Anyway, keep in mind I don't know, so the above list is just guesses.

Mark

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Thanks Mark,

Apparently the issue was this:

So why the Recall? Some units were produced where the mains 240V could potentially become live on the outer metal positively charged part of the barrel connector – despite this supposedly being the low voltage DC connector.

Taken from here: https://popeymongames.co.uk/2020/11/19/ ... y-warning/

I was hoping someone may have a recalled and non recalled so could do a side by side compare.

[flange]

I was going to add that I believed at the time it was the units that had black leads with white tracer but I see the link you posted already mentions that.

EDIT.

Picture of one with recall sticker.

[1024MAK]

Apparently the issue was this:

So why the Recall? Some units were produced where the mains 240V could potentially become live on the outer metal positively charged part of the barrel connector – despite this supposedly being the low voltage DC connector.

So, that narrows it down to these possibilities:

• PCB tracks for the mains not sufficiently clear (clearance distance) from the low voltage output side PCB tracks,
• Transformer problem,
• PCB or PCB mounted transformer able to break or come loose,
• Mains side wiring or output wiring may touch a conductor it should not be anywhere near (incorrectly routed or too long a length in the case, may be a lack of a plastic barrier between the mains side and the output side.

For the first three, there would not be a cheap and simple fix. The last point, that may have been fixable.

Mark

[flange]

Just found this...

"Meanwhile, there were some more production-related problems early in 1983 as Sinclair found itself having to recall Spectrum power supplies after it was discovered that "up to 14,000" of them could cause electric shocks.

That figure was later updated to 28,000 by Your Computer, which also revealed that the fault was down to the 240V input track on the power pack's circuit board running far too close to the 6V output.

This meant that a power spike in very humid weather could result in a shock."

Sinclair's MD, Nigel Searle, admitted that the supplies - just one batch from one supplier - "were not checked in detail for safety".

https://nosher.net/archives/computers/ads_024

[1024MAK]

That figure was later updated to 28,000 by Your Computer, which also revealed that the fault was down to the 240V input track on the power pack's circuit board running far too close to the 6V output.

Thank you flange

So out of my list, it's this one:

• PCB tracks for the mains not sufficiently clear (clearance distance) from the low voltage output side PCB.

Simple enough to check if you know what to look for.

Mark

[Guesser]

Simple enough to check if you know what to look for.

Yeah just hold onto the barrel plug while running the hot taps and shower to get the room nice and steamy!

[1024MAK]

Yeah just hold onto the barrel plug while running the hot taps and shower to get the room nice and steamy!

You'll forgive me (or maybe you won't), but I don't have any mains sockets (*) in the bathroom or shower room. And I get enough tingles from "modern" gadgets, brown goods and other appliances that use SMPSUs with their interference suppression capacitors connected between the mains side and the 'isolated' low voltage side.

And if I did actually want a "nice" large tingle, I could just dig out a cheap 'n' nasty "modern" far eastern made PSU where the "maker" uses a small cheap transformer that relies only on the (very thin) enamel wire coating for insulation and where you are lucky if the spacing between mains side PCB tracks and the 'low' voltage output PCB tracks is a very generous half a mm...

Mark

* apart from approved shaver sockets

[flange]

Mark

* apart from approved shaver sockets

Thank Christ I only wet shave then!

[flange]

Yeah just hold onto the barrel plug while running the hot taps and shower to get the room nice and steamy!

Goes in to bathroom cw duff power pack on a dodgy ext lead, gets it all nice and steamy and..........WAIT A MINUTE!!!

[Guesser]

* apart from approved shaver sockets

We don't even have that. I've had bemused comments whenever I've shared photos of my desk about why I have an electric toothbrush by my PC. Gotta charge it somewhere!