Fuse holder for PET 8032?

[johnq]

I've got a PET 8082-32 that I'm trying to repair and see first off the fuse at the back of the power supply is missing

Not sure what it's supposed to look like but I'm guessing it's a fuse holder that plugs or screws in.

Anyone know if a replacement is available from mouser/digikey and what model number I can search for?

I've seen the screw in type but don't think that's is as can't see how it screws in?

Worst case if I can find a replacement can they be easily removed ans I can replace the entire holder?

 

[Hugo Holden]

These are a standard (but not so standard) panel mount fuse holder for 6mm x 30mm fuses, that in the imperial equivalent were specified as 1/4" x 1&1/4" Occasionally they used 5x20 fuses.

The thing is, there were multiple manufacturers (usually its noted on their body that you can't see unless yo disassemble the power input area).

Each brand had a unique fitting to hold the fuse, some were bayonet fittings (probably not your version, but possible if there are no threads it will be a bayonet type) but in your case there is likely a deeply recessed thread that you cannot easily see. The threads are different between manufacturers as were the bayonet geometry.

They were done like this so that it was difficult to come into into contact with the live terminal via the fuse body while it was being removed.

The manufacturers were typically

Belling-Lee in the UK
Bussman
Amphenol
Schurter
Little fuse
and more Sato mainly in Japan.

I looked at my PET, but it has a different type to yours, I can tell because of the thickness of the perimeter of material around the insert. So Commodore must have mixed & matched brands at some point.

If somebody has a PET with that area open already and can spot the brand on the body of your version, that information in conjunction with the appearance/thickness of the rim around that insert, will probably allow you to find one in ebay and it would save you the trouble of having to replace the fuseholder body.

 

[johnq]

Thanks for the info. They don't make things easy with all these non standard parts.

Worst case I can replace the holder but lets hope it doesn't come to that and someone knows what specific brand this one is.

I've added another photo of the inside of the holder (as clear as I can get it) if it helps.

 

[johnq]

Curiosity got the better of me and I had to open it up.

Markings on it are:
FEU
6.3A 250V

So looks like this manufactured by Schurter. Model FEU. Variant 0031.1653

FEU - Shock-Safe Fuseholder, 5 x 20 / 6.3 x 32 mm, Slotted Cap

FEU - Shock-Safe Fuseholder, 5 x 20 / 6.3 x 32 mm, Slotted Cap

www.schurter.com

https://www.mouser.co.uk/ProductDetail/Schurter/0031.1653?qs=bpnLQM2ZShw7EtjzUrc5oQ%3D%3D

Fuse Size: 5mm x 20mm

Replacement cap:

Caps to FEU, FAU, FAC - Caps to Holder FEU, FEU (Med), FAU, FAC

Caps to FEU, FAU, FAC - Caps to Holder FEU, FEU (Med), FAU, FAC

www.schurter.com

O/N 0031.1663

https://www.mouser.co.uk/ProductDetail/Schurter/0031.1663?qs=TSScP84zSEoKfxEtWe6LlA%3D%3D

Just ordered one on eBay.

 

[Hugo Holden]

Curiosity got the better of me and I had to open it up.

Markings on it are:
FEU
6.3A 250V

So looks like this manufactured by Schurter. Model FEU. Variant 0031.1653

FEU - Shock-Safe Fuseholder, 5 x 20 / 6.3 x 32 mm, Slotted Cap

FEU - Shock-Safe Fuseholder, 5 x 20 / 6.3 x 32 mm, Slotted Cap

www.schurter.com

https://www.mouser.co.uk/ProductDetail/Schurter/0031.1653?qs=bpnLQM2ZShw7EtjzUrc5oQ%3D%3D

Fuse Size: 5mm x 20mm

Replacement cap:

Caps to FEU, FAU, FAC - Caps to Holder FEU, FEU (Med), FAU, FAC

Caps to FEU, FAU, FAC - Caps to Holder FEU, FEU (Med), FAU, FAC

www.schurter.com

O/N 0031.1663

https://www.mouser.co.uk/ProductDetail/Schurter/0031.1663?qs=TSScP84zSEoKfxEtWe6LlA%3D%3D

Just ordered one on eBay.

Saw that one on ebay too, I think you got the right one, most likely, but it would have been good to see the photo of its end where the screw insert is.

 

[robert_sissco]

I mean, unless you are going for a 100% accurate restoration, anything that fits a 6x30mm fuse and mount into the hole on the case would work as long as you wire it up correctly, shouldn't it?

I am just asking is all, since I am curious on this.

 

[ScottishColin]

I have an 8032-32B which was made in the USA and the fuse holder on the outside is marked "BUSS".

Colin.

 

[johnq]

Things just getting getting worse and worse for this for PET.

Got a fuse holder which is now working , and I've tested the switch - also working.

Next I did a continuity test between the mains plug to the transformer (mains side) and nothing. Both from live and neutral are dead - no continuity from the plug to the transformer.

If you look at my crude diagram the connections both go through some kind of class XY capacitor. So I'm guessing this is fried.

I've not seen one like this before and my online search is coming up empty.

Is there a modern replacement for this?

It's got a fair amount of rust on and I can only make out the following (Could not be 100% correct)

Funkentstorfilter (I think)
0.1uF + 2500uF XY + 2X
<something illegible> 250V 2A W.Germany

Update: Funkentstorfilter translates to Radio interference suppression filter

 

[daver2]

It is called remove it and put it in the bin (and not replacing it)...

Mains live in series with the switch and fuse holder to one side of the primary (mains) side of the transformer.

Mains neutral to the other side of the primary (mains) side of the transformer (unless the switch is a 2-pole device).

Mains earth to the case - this is IMPORANT.

It probably is fried - but (just to check) test the mains transformer primary winding out to make sure it is OK. BEWARE, do not touch the metal probes of your multimeter. If the transformer is working, you can get a shock from the back emf that is still unpleasant!

See here for a typical arrangement: https://www.zimmers.net/anonftp/pub/cbm/schematics/computers/pet/8032/8032051-3.gif.

Dave

 

[johnq]

Thanks Dave. Was looking around for that schematic.

I thought it could be removed as it just looks like a noise suppression device - but wasn't sure.

It's a single pole switch. I've beep tested the mains primary and secondary windings and they all look good, also no short to ground.

 

[daver2]

Excellent.

These RFI filters were probably fitted to pass regulations in various countries. I think these filters (certainly on mine) are in the mains connector on the rear of the PET. Of course, if you have a wire going through a grommet - this cannot be the case!

Dave

 

[johnq]

Success - yanked it out and it looks like the transformer is working.

Getting 20VAC, 15VAC and 8.5-0-8.5VAC

Now onto the next phase of fixing the motherboard. Will double check all the voltage rails once they do through the rectifiers/regulators.

 

[daver2]

Excellent!

Tune for minimum smoke ...

Dave

 

[MindWalker]

That RFI filter looks very similar to the one in my 8032. The filter in my unit blew during the first 15min of usage when I got the machine. There was bang and smoke, I think yours has done the same as the red cap has been pushed out of the casing. In my case the filter shorted the mains input when it blew.

The text on my filter is: 0,1uF + 2x2500pF XY+2X, 100uH 250V 2A.

I removed the filter completely, although I'd kinda like to replace it eventually with something broadly similar.

 

[johnq]

That looks identical. A lot of the writing on mine is rusted but what I can read matches yours.

Good to know the exact specs should one day I decide to replace it.

 

[daver2]

Mouser 562-851-05/6. It is not the same physical thing - but functionally it should be fine.

I will have a look for something with similar physical characteristics for you (if you want something that has identical mountings).

Dave

 

[Hugo Holden]

One good move, if you are handy with metalwork, is to fit a panel mount IEC Connector, that way your PET doesn't have a line cord dangling out of it . Also, if you really wanted (I don't usually do it as in the case of the PET it is pointless) you can fit an IEC Connector with the integral line filter inside it. Since the metalwork is steel, when I fit an IEC connector, I always smooth and paint the cut edges of the rectangular hole to prevent rusting. There are varoius panel mount IEC connectors, retained by either two screws or that clip in. for my PET I used a clip in connector.

Here is the thread where I mentioned this in the past:

https://forum.vcfed.org/index.php?threads/the-power-cord-dilemma.1246149/#post-1357794

 

[johnq]

Thanks, that's a great idea. I might do that once I've sorted out all the other issus.