Commodore PET 2001 voltage regulators

[Slothie]

I had a ZD-415 which is the same as that soldering station, only got to use it for a short time before I got ill and all my stuff got put into storage, but it worked well enough. Several of my favorite youtubers have one and seem to like it, as long as you make sure to clean it out regularly. One tip I saw was that if the tube leading to the nozzle gets blocked with solder, leaving it switched on with the tip pointing vertically down causes heat to convect upward and melt the blocking solder. Although I imagine if you clean it out every session of use that won't become an issue. The tips were easy enough to get a year or 2 ago, I would imagine if farnell is stocking it then they will for some time.

[retromit]

Originally Posted by Slothie

I had a ZD-415 which is the same as that soldering station, only got to use it for a short time before I got ill and all my stuff got put into storage, but it worked well enough. Several of my favorite youtubers have one and seem to like it, as long as you make sure to clean it out regularly. One tip I saw was that if the tube leading to the nozzle gets blocked with solder, leaving it switched on with the tip pointing vertically down causes heat to convect upward and melt the blocking solder. Although I imagine if you clean it out every session of use that won't become an issue. The tips were easy enough to get a year or 2 ago, I would imagine if farnell is stocking it then they will for some time.

Yes, I clean the nozzle after each use, then the container after a few uses (depends on how much desoldering I’ve been doing). I bought a few spares with mine (tips, filters, containers), but I think I’ve only changed the filters a couple of times, and the tip once, so looks to be quite economical with those.

Tim.

[SiriusHardware]

If the Duratool unit is the one I'm thinking of then the only criticism that I have (of the example I have used) is that the Tube retainers don't retreat far enough from the tube to allow the glass tube to slip easily in and out. Maybe this has been improved since the one I've used was made. Having said that, it did the actual job perfectly well and for about a tenth of the price of the powered Metcal and Weller units that I have access to.

There was a suggestion, possibly somewhere on this forum, for how to address the 'tight fit tube' problem by modifications to the handpiece to allow the tube retainers to move further apart.

I'm glad the replacement 3446 has fixed that IEEE problem - I really expected it would but I'm always nervous when we ask people to spend money on exotic, potentially expensive parts.

[retromit]

Originally Posted by SiriusHardware

If the Duratool unit is the one I'm thinking of then the only criticism that I have (of the example I have used) is that the Tube retainers don't retreat far enough from the tube to allow the glass tube to slip easily in and out. Maybe this has been improved since the one I've used was made. Having said that, it did the actual job perfectly well and for about a tenth of the price of the powered Metcal and Weller units that I have access to.

There was a suggestion, possibly somewhere on this forum, for how to address the 'tight fit tube' problem by modifications to the handpiece to allow the tube retainers to move further apart.

I'm glad the replacement 3446 has fixed that IEEE problem - I really expected it would but I'm always nervous when we ask people to spend money on exotic, potentially expensive parts.

Thanks again for the advice and help about the 3446. Things all seem happy at the moment, so that's good news!

Yes, I'd agree about the removal of the glass tube for cleaning being a bit fiddly/restrictive. It is a tight fit in the desolder gun, but I'll have to try and look to see if there is something that could be done to make it a little easier.

If there was a further modification that I could make then it would be the desolder gun holder bracket on the main unit. It does sit fine, but feel the bracket could be slightly longer to accommodate the desolder gun a little better.

Having said that, I feel it's a great piece of kit and has worked fine for me. I've only ever used this unit as I'm just a hobbyist, but for the price it seemed a good buy.

Tim.

[SiriusHardware]

For information, here are the specific posts from the thread I thought I had seen. May not be the same Duratool model but appears to relate to the same problem (glass tube difficult to insert and remove because the retaining ends do not move far enough away from the tube to allow it to be inserted or removed cleanly.)

https://www.vintage-radio.net/forum/...58&postcount=1

https://www.vintage-radio.net/forum/...3&postcount=16

[ScottishColin]

Well done. It's nice to see another PET back in the land of the living.

Colin.

Originally Posted by retromit

Hi. Just thought I'd give a quick update. The ICs from Cricklewood Electornics arrived today, so the replacement UA7 was put in place. The voltages (after running the POKE) on pins 9, 11, 13, 15 were all identical, and the two POKE/PEEK commands both returned the correct values.

I then loaded the IEEE code, and it looks like all is well after running it. I left the code just looping for 1 hour 30 minutes, and each pass went through successfully.

So it looks like the replacement chip is all good, and the IEEE seems a lot happier!

Just want to say many thanks once again for all the help and support provided. It really has been appreciated.

Tim.

[Timbucus]

Originally Posted by SiriusHardware

If the Duratool unit is the one I'm thinking of then the only criticism that I have (of the example I have used) is that the Tube retainers don't retreat far enough from the tube to allow the glass tube to slip easily in and out. Maybe this has been improved since the one I've used was made. Having said that, it did the actual job perfectly well and for about a tenth of the price of the powered Metcal and Weller units that I have access to.

There was a suggestion, possibly somewhere on this forum, for how to address the 'tight fit tube' problem by modifications to the handpiece to allow the tube retainers to move further apart..

I have one and I just unscrew the handle when I clean the glass tube - its a pain but, doesn't take too long - just be careful not to lose the spring...

I agree the rest feels like it is not enough but works.

Otherwise it desolders great if you follow the rules of working horizontally, keeping the trigger pressed a moment as you move away from the piece, circle motion to gently move the lead and use the thin metal to keep the blobs away from the back.

[ajgriff]

Thanks for all the useful information about the desoldering station. Have also watched some of the online videos. If the PET is going to get an SD2PET for Christmas I might well ask Santa for a Duratool D00672. Seems fair enough to me. CPC seems to be competitive in terms of price at present and has plenty in stock.

With the SD2PET I'm partly tempted because of the current price reduction which I assume is down to the impending introduction of a more expensive 2031 Style version. Don't see any great advantage in that personally.

I don't how bad the rust spots are on Tim's machine but I'd definitely recommend a proper respray if they're anything other than very superficial. Colin has recent experience of doing this of course and I believe he used Peugeot Bianca White rattle cans. For my part I used white radiator enamel on the monitor only as the main case didn't need attention. It's pretty much impossible to recreate the original textured finish but I don't think many people would notice the lack. One thing I would recommend is the use of primer once the old paint has been stripped. Commodore didn't bother at their office furniture factory.

Alan

[retromit]

Originally Posted by ScottishColin

Well done. It's nice to see another PET back in the land of the living.

Colin.

Thanks Colin. Once again, many thanks for the replacement 6502 you sent over.

Tim.

[retromit]

Originally Posted by SiriusHardware

For information, here are the specific posts from the thread I thought I had seen. May not be the same Duratool model but appears to relate to the same problem (glass tube difficult to insert and remove because the retaining ends do not move far enough away from the tube to allow it to be inserted or removed cleanly.)

https://www.vintage-radio.net/forum/...58&postcount=1

https://www.vintage-radio.net/forum/...3&postcount=16

Many thanks for the links. The desolder gun looks to be the same, so I'll have to see what can be done to mine. It would certainly make it a bit easier for cleaning. I also like the other modifications that they have made, especially for the cleaning rods - a thing I'm always losing/looking for!

Thanks,
Tim.

[retromit]

Originally Posted by ajgriff

I don't how bad the rust spots are on Tim's machine but I'd definitely recommend a proper respray if they're anything other than very superficial. Colin has recent experience of doing this of course and I believe he used Peugeot Bianca White rattle cans. For my part I used white radiator enamel on the monitor only as the main case didn't need attention. It's pretty much impossible to recreate the original textured finish but I don't think many people would notice the lack. One thing I would recommend is the use of primer once the old paint has been stripped. Commodore didn't bother at their office furniture factory.

Alan

I've added a few pictures of the rust spots. The worse area seems to be the inside of the monitor case (first two pictures below). I can't see any rust issue on the inside of the case. There are a few areas on the top of the case (under the monitor), and a few on the sides. Since I've owned the PET I haven't cleaned anything as yet. I tried cleaning a few of the rust spots on the case side, and they are improved (pictures three and four). With them not being too bad, I'm wondering if they could be cleaned with white vinegar (with only having a few spots)?

The bottom of the (inside) of the monitor looks pretty bad, so I'm thinking the CRT may need to be taken out in order to scrub, then re-paint.

Just wonder if anyone has any thoughts?

Thanks,
Tim.

[retromit]

Just as a reference, here's a picture of the PET with no cleaning, etc.

[SiriusHardware]

Assuming it will be kept in comfortable surroundings now, I might be tempted to say keep it as it is as it doesn't look bad at all from the front.

The only thing I would wonder is, will the rust still develop further if the machine is kept in a dry, stable environment, or will it stay dormant? This is not really my area, but at the moment it is at least still - physically - completely original.

[retromit]

Originally Posted by SiriusHardware

Assuming it will be kept in comfortable surroundings now, I might be tempted to say keep it as it is as it doesn't look bad at all from the front.

The only thing I would wonder is, will the rust still develop further if the machine is kept in a dry, stable environment, or will it stay dormant? This is not really my area, but at the moment it is at least still - physically - completely original.

Yes, the PET will be kept in the house. It's the thing I'm not sure of as well; if the rust will continue? I was thinking the white vinegar would neutralise it (on smaller patches), but was also a bit concerned about the inside of the monitor.

Some more may come off when I clean further. Overall, it does look quite nice, just the few spots around the case, and the inside of the monitor case.

Tim.

[ScottishColin]

I guess all I'd say is that it's very difficult (i.e. almost impossible) to touchup a small area without it being obvious. The paint will have faded over the years and finding an exact match will prove very difficult. If you do decide to paint/spray, you're probably going to have to do the whole thing (which is what I did but mine was badly rusted).

If it's only small areas, I'd probably leave well alone.

Colin.

[ScottishColin]

Oh - and removing the CRT and the board from inside the minitor shell isn't for the faint hearted either. Perfectly possible to do it but you'll have to discharge the CRT to stop yourself getting zapped by very high voltages. The plastic fascia on the front of the CRT has four 'legs' inside the case which have to be cut off and glues back in place to remove/replace it too.

I'd guess the rust inside the CRT is because they never applied any undercoat and probably only ever gave it one coat of paint as it isn't in plain sight.

Happy to help if you do decide to respray, but a good clean would be where I'd start, and research discharging CRTs if you're going to do it.

Colin.

Colin.

[retromit]

Originally Posted by ScottishColin

Oh - and removing the CRT and the board from inside the minitor shell isn't for the faint hearted either. Perfectly possible to do it but you'll have to discharge the CRT to stop yourself getting zapped by very high voltages. The plastic fascia on the front of the CRT has four 'legs' inside the case which have to be cut off and glues back in place to remove/replace it too.

I'd guess the rust inside the CRT is because they never applied any undercoat and probably only ever gave it one coat of paint as it isn't in plain sight.

Happy to help if you do decide to respray, but a good clean would be where I'd start, and research discharging CRTs if you're going to do it.

Colin.

Colin.

I think for the case, I'm more inclined to leave it as it is (providing it doesn't get any worse). Give it a really good clean and maybe treat some of the small areas with white vinegar, but nothing else. The case itself has a few battlescars, but I don't really want to do anything that I don't need to.

That's a good call about the rust in the monitor, and thanks for the information. I'll be very honest and say I really don't fancy discharging the CRT, and removing everything but if it's what I need to do, then I may have to do it. It's certainly the area with the most rust, and not easy to clean at all.

Tim.

[ajgriff]

Really tricky one and very much a personal judgement call. More cleaning plus an application of phosphoric acid based rust killer would probably be better than vinegar in terms of disguise and neutralisation. Even in a warm room there can be plenty of humidity to encourage further rust development underneath the very thin layer of original paint. For me things like 'originality' and 'showing its history' are subordinate to making something appear 'well looked after'. Again very much a personal choice. I think the bottom (inside) of the monitor could be given the rust treatment by just releasing the PCB without removing or discharging the CRT. Colin can advise.

If you decide on a more comprehensive respray there'll be a lot of work involved in achieving a pleasing outcome. Apart from dismantling, masking, and label preservation it would really be necessary to strip the old paint. The rust could then be cleaned off properly before using rust killer as further insurance.

As far as I know the only way to replicate the slightly textured finish and match the colour precisely is to enlist the services of a professional powder coating company. Not an inexpensive option! However I still think that an entirely satisfactory result can be achieved with colour matched automotive rattle cans. With practice it's even possible to produce a slightly powdery finish by spraying at an excessive distance for the final coat.

Just for fun I've attached an image taken from the web showing how not to do the respray. Looks like woodchip wallpaper. No idea how it was done but a smooth gloss finish would have looked much better in my view.

Alan

[ScottishColin]

I rubbed down ( a lot) and then sprayed on top of what was left. Didn't try to emulate the previous finish. I'm glad I didn't looking at that picture.

Colin.

Originally Posted by ajgriff

Really tricky one and very much a personal judgement call. More cleaning plus an application of phosphoric acid based rust killer would probably be better than vinegar in terms of disguise and neutralisation. Even in a warm room there can be plenty of humidity to encourage further rust development underneath the very thin layer of original paint. For me things like 'originality' and 'showing its history' are subordinate to making something appear 'well looked after'. Again very much a personal choice. I think the bottom (inside) of the monitor could be given the rust treatment by just releasing the PCB without removing or discharging the CRT. Colin can advise.

If you decide on a more comprehensive respray there'll be a lot of work involved in achieving a pleasing outcome. Apart from dismantling, masking, and label preservation it would really be necessary to strip the old paint. The rust could then be cleaned off properly before using rust killer as further insurance.

As far as I know the only way to replicate the slightly textured finish and match the colour precisely is to enlist the services of a professional powder coating company. Not an inexpensive option! However I still think that an entirely satisfactory result can be achieved with colour matched automotive rattle cans. With practice it's even possible to produce a slightly powdery finish by spraying at an excessive distance for the final coat.

Just for fun I've attached an image taken from the web showing how not to do the respray. Looks like woodchip wallpaper. No idea how it was done but a smooth gloss finish would have looked much better in my view.

Alan

[SiriusHardware]

the monitor could be given the rust treatment by just releasing the PCB without removing the CRT

It could, potentially, but the idea of having the PCB assembly whanging about near the tube neck while attempting to carry out fairly heavy physical work on the inside of the monitor casing makes me wince, to be honest.

Damage the tube and you'll be in a whole new world of pain. I have no idea how easy it is to find equivalent replacement tubes and I wouldn't want to be in the position of having to find out.