Commodore PET 2001 voltage regulators - Page 20 - UK Vintage Radio Repair and Restoration Discussion Forum

retromit · 13th Nov 2021, 8:54 pm

Another thing I noticed was some rust on the transformer. It looks to be just on the top, on each side where the screws are. I was thinking of just going over this gently to remove the rust, then (potentially) the rust neutraliser on this (being careful on where it is painted).

The rest of the transformer looks to be okay, but would welcome any ideas/advice on what should be done here.

Tim.

Slothie · 13th Nov 2021, 9:20 pm

A gentle rub with wire wool and WD40 would do it, its effective for removing rust on sheetmetal. Just don't make it slippery and drop it on your foot!

SiriusHardware · 13th Nov 2021, 9:39 pm

Well done getting the bits out.

If you are putting liquid anywhere in this, be careful where it ends up. IPA should evaporate quite quickly but lubricants could hang around for a long time if they get into the transformer windings and other unwelcome places. When cleaning things up try not to nudge any adjustments such as the positions of pots, etc.

The laminations of the transformer are held together by long machine screws which go all the way through from one side to the other, those screw heads will go through to nuts on the corresponding corners on the underside of the transformer so in theory you can loosen and remove the screws / nuts to free that rusty strip of metal and remove and treat it however you like, then put it back on and screw it back together.

However, I'm a great exponent of 'If it isn't broken, don't fix it' and I would be inclined to try to rub that muck off the transformer but not do much else to it - you don't really want metal filings all over the place, so I would hesitate to use anything really abrasive on it in-situ.

Slothie · 13th Nov 2021, 9:56 pm

Getting back to an earlier point, personally I wouldn't do anything to the paintwork other than clean it, the rust isn't bad at all. Maybe when its clean a rub over with a soft cloth and some Mr Sheen to protect it maybe

I say furniture polish, because when I was a lad my mum used to give the PET a once-over with the polish when she was doing the dusting and it never did it any harm that I recall. Looking at the close up of the paint, that's how I recall mine, in comparison its a bit more subtle than the "woodchip" picture shown earlier!

ajgriff · 13th Nov 2021, 10:34 pm

Such good progress. I have a pathological dislike of rust and have been known to go to great lengths in an effort to elminate it. However I think the consensus here will be that you don't need to go too far with your PET although I wouldn't hesitate to use a wipe of rust killer on the top of the case. I'm assuming that the rust killer doesn't show any signs of lifting the paint inside the monitor casing of course. Primer on the inside of the monitor is worthwhile but I'd give it a top coat of gloss as well for better long term protection. Primer alone is quite porous. I always use old newspapers or magazines when masking as it makes the masking tape go further.

You should definitely remove the transformer if you decide to use wire wool on it. I'd just give it a wipe with an oily rag once you've rubbed down the rust. This'll just leave a thin film of protective oil. Goes without saying that you don't want to get oil anywhere near areas you're going to paint.

Furniture polish spray is fine but make sure it's silicone free (most brands are these days). Silicones creep pernisciously and interfere with electrical contacts. Keyboard keys are particularly vulnerable.

Looking forward to seeing the finished article.

Alan

Telleadict · 14th Nov 2021, 4:06 pm

Hello

How about a wipe over with some car wax if you have some on the still sound paint. That should leave a protective film that will last a long time indoors.

Will

ScottishColin · 14th Nov 2021, 5:32 pm

Here's mine - yours is in better nick than mine. I think I had had enough by then....I'll be interested to see how much you can get off.

I also think I put mine on 180 degrees the wrong way round but I'm not changing it now.

Colin.

Quote:

Originally Posted by retromit

Another thing I noticed was some rust on the transformer. It looks to be just on the top, on each side where the screws are. I was thinking of just going over this gently to remove the rust, then (potentially) the rust neutraliser on this (being careful on where it is painted).

The rest of the transformer looks to be okay, but would welcome any ideas/advice on what should be done here.

Tim.

retromit · 14th Nov 2021, 9:59 pm

Quote:

Originally Posted by ajgriff

Such good progress. I have a pathological dislike of rust and have been known to go to great lengths in an effort to elminate it. However I think the consensus here will be that you don't need to go too far with your PET although I wouldn't hesitate to use a wipe of rust killer on the top of the case. I'm assuming that the rust killer doesn't show any signs of lifting the paint inside the monitor casing of course. Primer on the inside of the monitor is worthwhile but I'd give it a top coat of gloss as well for better long term protection. Primer alone is quite porous. I always use old newspapers or magazines when masking as it makes the masking tape go further.

You should definitely remove the transformer if you decide to use wire wool on it. I'd just give it a wipe with an oily rag once you've rubbed down the rust. This'll just leave a thin film of protective oil. Goes without saying that you don't want to get oil anywhere near areas you're going to paint.

Furniture polish spray is fine but make sure it's silicone free (most brands are these days). Silicones creep pernisciously and interfere with electrical contacts. Keyboard keys are particularly vulnerable.

Looking forward to seeing the finished article.

Alan

After leaving the rust killer for a while, it doesn't seem to be lifting any of the paint. In fact, it's quite easy to just rub it away from those areas. For the rusted area, it worked a treat and was able to put down the primer. Now the primer has dried, I've sprayed two coats of gloss white on the inside so am now just waiting for it to harden off. Fingers crossed, I'll be able to get the CRT abck in the case on Tuesday.

For the other areas on the case, I've just applied a very light dab with a cotton bud. There has been no adverse reaction, so hopefully it's okay. After that, it will just be cleaned some more and I think that should be the casing done.

Then we're on to cleaning the keyboard...

Tim.

retromit · 14th Nov 2021, 10:06 pm

Quote:

Originally Posted by ScottishColin

Here's mine - yours is in better nick than mine. I think I had had enough by then....I'll be interested to see how much you can get off.

I also think I put mine on 180 degrees the wrong way round but I'm not changing it now.

Colin.

Quote:

Originally Posted by retromit

Another thing I noticed was some rust on the transformer. It looks to be just on the top, on each side where the screws are. I was thinking of just going over this gently to remove the rust, then (potentially) the rust neutraliser on this (being careful on where it is painted).

The rest of the transformer looks to be okay, but would welcome any ideas/advice on what should be done here.

Tim.

After reading (and I still haven't been through all the posts yet) the huge thread for your PET, then reading your blog with the pictures of the restoration, I can fully understand when you say you'd had enough! I have to say though, your PET really turned out nice. It certainly looked like a lot of work.

Yes, I'll be finishing the case and then starting on the keyboard next. I think after that I'll start looking over the transformer. I'll be following the consensus here by removing it for any work. Hopefully it will just be surface rust like what I've seem in the monitor casing, but at least I’ll be able to get a better look when it’s out.

Tim

retromit · 14th Nov 2021, 10:10 pm

Just a quick update. The monitor casing has been primed, and has now had two coats of gloss. I'm just lightly cleaning the PCB, mainly getting rid of surface debris, but when the gloss has hardened, then I should be able to get it all put back together again. I'm going to give it plenty of time to dry, so hopefully on Tuesday, the monitor will be back together.

Tim.

retromit · 14th Nov 2021, 10:25 pm

I do have a question about the anode cap. I've attached a couple of pictures with the part in question highlighted. When discharging/removing the cap I didn't pay too much attention (nor really saw) how it was connected. When I put everything back together, the two prongs on the cap will be put back into the hole on the CRT in order to hold it in place; however, I'm not sure if the 'clip' I've highlighted should also be in the hole with the prongs, or if it sits outside? I'm just a bit unsure of this. NB. The white reside on the underside of the cap was there when it was removed.

Tim.

ScottishColin · 14th Nov 2021, 10:28 pm

Here's your next one....

https://www.ebay.co.uk/itm/144282339720

Colin.

Quote:

Originally Posted by retromit

Just a quick update. The monitor casing has been primed, and has now had two coats of gloss. I'm just lightly cleaning the PCB, mainly getting rid of surface debris, but when the gloss has hardened, then I should be able to get it all put back together again. I'm going to give it plenty of time to dry, so hopefully on Tuesday, the monitor will be back together.

Tim.

ScottishColin · 14th Nov 2021, 10:30 pm

Can't remember if I pointed you at this video - I found it very useful for the keyboard.

https://www.youtube.com/watch?v=xkoVVbdky_o

Colin.

Quote:

Originally Posted by retromit

Quote:

Originally Posted by ScottishColin

Here's mine - yours is in better nick than mine. I think I had had enough by then....I'll be interested to see how much you can get off.

I also think I put mine on 180 degrees the wrong way round but I'm not changing it now.

Colin.

Quote:

Originally Posted by retromit

Another thing I noticed was some rust on the transformer. It looks to be just on the top, on each side where the screws are. I was thinking of just going over this gently to remove the rust, then (potentially) the rust neutraliser on this (being careful on where it is painted).

The rest of the transformer looks to be okay, but would welcome any ideas/advice on what should be done here.

Tim.

After reading (and I still haven't been through all the posts yet) the huge thread for your PET, then reading your blog with the pictures of the restoration, I can fully understand when you say you'd had enough! I have to say though, your PET really turned out nice. It certainly looked like a lot of work.

Yes, I'll be finishing the case and then starting on the keyboard next. I think after that I'll start looking over the transformer. I'll be following the consensus here by removing it for any work. Hopefully it will just be surface rust like what I've seem in the monitor casing, but at least I’ll be able to get a better look when it’s out.

Tim

retromit · 14th Nov 2021, 10:33 pm

Quote:

Originally Posted by ScottishColin

Here's your next one....

https://www.ebay.co.uk/itm/144282339720

Colin.

Quote:

Originally Posted by retromit

Just a quick update. The monitor casing has been primed, and has now had two coats of gloss. I'm just lightly cleaning the PCB, mainly getting rid of surface debris, but when the gloss has hardened, then I should be able to get it all put back together again. I'm going to give it plenty of time to dry, so hopefully on Tuesday, the monitor will be back together.

Tim.

Oh, good grief! I've certainly got off lightly looking over that!

Tim.

retromit · 14th Nov 2021, 10:38 pm

Quote:

Originally Posted by ScottishColin

Can't remember if I pointed you at this video - I found it very useful for the keyboard.

https://www.youtube.com/watch?v=xkoVVbdky_o

Colin.

Quote:

Originally Posted by retromit

Quote:

Originally Posted by ScottishColin

Here's mine - yours is in better nick than mine. I think I had had enough by then....I'll be interested to see how much you can get off.

I also think I put mine on 180 degrees the wrong way round but I'm not changing it now.

Colin.

After reading (and I still haven't been through all the posts yet) the huge thread for your PET, then reading your blog with the pictures of the restoration, I can fully understand when you say you'd had enough! I have to say though, your PET really turned out nice. It certainly looked like a lot of work.

Yes, I'll be finishing the case and then starting on the keyboard next. I think after that I'll start looking over the transformer. I'll be following the consensus here by removing it for any work. Hopefully it will just be surface rust like what I've seem in the monitor casing, but at least I’ll be able to get a better look when it’s out.

Tim

You did, Colin, thanks. I looked over it a couple times when I thought I had an issue with the shift key and found it really useful. I'll certainly be going through it again for when I remove and clean the keysboard.

Tim.

ajgriff · 15th Nov 2021, 3:51 pm

Quote:

Originally Posted by retromit

When I put everything back together, the two prongs on the cap will be put back into the hole on the CRT in order to hold it in place; however, I'm not sure if the 'clip' I've highlighted should also be in the hole with the prongs, or if it sits outside? I'm just a bit unsure of this. NB. The white reside on the underside of the cap was there when it was removed.

All three elements should be inserted into the tube's recess. Easier to do with the cap folded back so you can see things more clearly.

As for the white deposit it looks like an accumulation of general muck which needs cleaning off with meths or IPA. In more recent times some manufacturers used silicone sealant under the cap but I think it's unlikely that Commodore did that back then.

Make sure the tube around the cap is really clean together with the cable itself and the connection to the transformer. This will reduce the chances of arcing occurring in the future.

Alan

SiriusHardware · 15th Nov 2021, 4:31 pm

Another point, when you put it all back together try to route the thick high voltage cable so that it is 'airborne' all the way between the top of the LOPT and the tube, and in particular, not touching against the metal cabinet at any point along the way and not resting on any of the other components on the PCB.

Although the insulation on that cable is very thick and heavy it's still not a good idea to tempt the high voltage on the inner core to jump through the insulation to any nearby earth or any other circuit point. Keep the cable a clear distance away from every other thing in the monitor.

retromit · 15th Nov 2021, 4:38 pm

Quote:

Originally Posted by ajgriff

Quote:

Originally Posted by retromit

When I put everything back together, the two prongs on the cap will be put back into the hole on the CRT in order to hold it in place; however, I'm not sure if the 'clip' I've highlighted should also be in the hole with the prongs, or if it sits outside? I'm just a bit unsure of this. NB. The white reside on the underside of the cap was there when it was removed.

All three elements should be inserted into the tube's recess. Easier to do with the cap folded back so you can see things more clearly.

As for the white deposit it looks like an accumulation of general muck which needs cleaning off with meths or IPA. In more recent times some manufacturers used silicone sealant under the cap but I think it's unlikely that Commodore did that back then.

Make sure the tube around the cap is really clean together with the cable itself and the connection to the transformer. This will reduce the chances of arcing occurring in the future.

Alan

Thanks. I had wondered if all needed to be inserted, so that's great. I've cleaned an awful lot of black (and sticky) debris from the cap, so will now clean off the white stuff. I'll just be happy when this is all back in the case!

Tim.

retromit · 15th Nov 2021, 4:40 pm

Quote:

Originally Posted by SiriusHardware

You may even have a sizeable quantity of the original owner's DNA there.

Oh good grief; what a thought!

Tim.

retromit · 15th Nov 2021, 6:18 pm

I’m having a lot of problems trying to get the anode cap back on with all three bits inserted. The two pronged legs go in fine, but there just doesn’t seem to be enough room to try and get the third, smaller, bit in. If I try and lever that in first, then I can’t get the pronged legs in. I’ve tried a few different ways, but am worried about causing any damage.

Just wondering if anyone has any suggestions?

Thanks,
Tim.

13th Nov 2021, 8:54 pm	#381
retromit Pentode Join Date: Oct 2021 Location: Falkirk, Scotland, UK Posts: 140	Re: Commodore PET 2001 voltage regulators Another thing I noticed was some rust on the transformer. It looks to be just on the top, on each side where the screws are. I was thinking of just going over this gently to remove the rust, then (potentially) the rust neutraliser on this (being careful on where it is painted). The rest of the transformer looks to be okay, but would welcome any ideas/advice on what should be done here. Tim. Attached Thumbnails

13th Nov 2021, 9:20 pm	#382
Slothie Octode Join Date: Apr 2018 Location: Newbury, Berkshire, UK. Posts: 1,287	Re: Commodore PET 2001 voltage regulators A gentle rub with wire wool and WD40 would do it, its effective for removing rust on sheetmetal. Just don't make it slippery and drop it on your foot!

13th Nov 2021, 9:39 pm	#383
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,575	Re: Commodore PET 2001 voltage regulators Well done getting the bits out. If you are putting liquid anywhere in this, be careful where it ends up. IPA should evaporate quite quickly but lubricants could hang around for a long time if they get into the transformer windings and other unwelcome places. When cleaning things up try not to nudge any adjustments such as the positions of pots, etc. The laminations of the transformer are held together by long machine screws which go all the way through from one side to the other, those screw heads will go through to nuts on the corresponding corners on the underside of the transformer so in theory you can loosen and remove the screws / nuts to free that rusty strip of metal and remove and treat it however you like, then put it back on and screw it back together. However, I'm a great exponent of 'If it isn't broken, don't fix it' and I would be inclined to try to rub that muck off the transformer but not do much else to it - you don't really want metal filings all over the place, so I would hesitate to use anything really abrasive on it in-situ.

13th Nov 2021, 9:56 pm	#384
Slothie Octode Join Date: Apr 2018 Location: Newbury, Berkshire, UK. Posts: 1,287	Re: Commodore PET 2001 voltage regulators Getting back to an earlier point, personally I wouldn't do anything to the paintwork other than clean it, the rust isn't bad at all. Maybe when its clean a rub over with a soft cloth and some Mr Sheen to protect it maybe I say furniture polish, because when I was a lad my mum used to give the PET a once-over with the polish when she was doing the dusting and it never did it any harm that I recall. Looking at the close up of the paint, that's how I recall mine, in comparison its a bit more subtle than the "woodchip" picture shown earlier!

13th Nov 2021, 10:34 pm	#385
ajgriff Nonode Join Date: May 2004 Location: Halifax, West Yorkshire, UK. Posts: 2,587	Re: Commodore PET 2001 voltage regulators Such good progress. I have a pathological dislike of rust and have been known to go to great lengths in an effort to elminate it. However I think the consensus here will be that you don't need to go too far with your PET although I wouldn't hesitate to use a wipe of rust killer on the top of the case. I'm assuming that the rust killer doesn't show any signs of lifting the paint inside the monitor casing of course. Primer on the inside of the monitor is worthwhile but I'd give it a top coat of gloss as well for better long term protection. Primer alone is quite porous. I always use old newspapers or magazines when masking as it makes the masking tape go further. You should definitely remove the transformer if you decide to use wire wool on it. I'd just give it a wipe with an oily rag once you've rubbed down the rust. This'll just leave a thin film of protective oil. Goes without saying that you don't want to get oil anywhere near areas you're going to paint. Furniture polish spray is fine but make sure it's silicone free (most brands are these days). Silicones creep pernisciously and interfere with electrical contacts. Keyboard keys are particularly vulnerable. Looking forward to seeing the finished article. Alan

14th Nov 2021, 4:06 pm	#386
Telleadict Hexode Join Date: Dec 2005 Location: Nr. York, North Yorkshire, UK. Posts: 348	Re: Commodore PET 2001 voltage regulators Hello How about a wipe over with some car wax if you have some on the still sound paint. That should leave a protective film that will last a long time indoors. Will

14th Nov 2021, 10:10 pm	#390
retromit Pentode Join Date: Oct 2021 Location: Falkirk, Scotland, UK Posts: 140	Re: Commodore PET 2001 voltage regulators Just a quick update. The monitor casing has been primed, and has now had two coats of gloss. I'm just lightly cleaning the PCB, mainly getting rid of surface debris, but when the gloss has hardened, then I should be able to get it all put back together again. I'm going to give it plenty of time to dry, so hopefully on Tuesday, the monitor will be back together. Tim. Attached Thumbnails

14th Nov 2021, 10:25 pm	#391
retromit Pentode Join Date: Oct 2021 Location: Falkirk, Scotland, UK Posts: 140	Re: Commodore PET 2001 voltage regulators I do have a question about the anode cap. I've attached a couple of pictures with the part in question highlighted. When discharging/removing the cap I didn't pay too much attention (nor really saw) how it was connected. When I put everything back together, the two prongs on the cap will be put back into the hole on the CRT in order to hold it in place; however, I'm not sure if the 'clip' I've highlighted should also be in the hole with the prongs, or if it sits outside? I'm just a bit unsure of this. NB. The white reside on the underside of the cap was there when it was removed. Tim. Attached Thumbnails

15th Nov 2021, 4:31 pm	#397
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,575	Re: Commodore PET 2001 voltage regulators Another point, when you put it all back together try to route the thick high voltage cable so that it is 'airborne' all the way between the top of the LOPT and the tube, and in particular, not touching against the metal cabinet at any point along the way and not resting on any of the other components on the PCB. Although the insulation on that cable is very thick and heavy it's still not a good idea to tempt the high voltage on the inner core to jump through the insulation to any nearby earth or any other circuit point. Keep the cable a clear distance away from every other thing in the monitor. Last edited by SiriusHardware; 15th Nov 2021 at 4:45 pm.

15th Nov 2021, 6:18 pm	#400
retromit Pentode Join Date: Oct 2021 Location: Falkirk, Scotland, UK Posts: 140	Re: Commodore PET 2001 voltage regulators I’m having a lot of problems trying to get the anode cap back on with all three bits inserted. The two pronged legs go in fine, but there just doesn’t seem to be enough room to try and get the third, smaller, bit in. If I try and lever that in first, then I can’t get the pronged legs in. I’ve tried a few different ways, but am worried about causing any damage. Just wondering if anyone has any suggestions? Thanks, Tim.