Siemens T1000 restoration

[kphill01]

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Greetings and Happy New Year! I hope 2021 will be a better year for everyone.

I have done a little more work on my T1000. I wanted to disassemble the typing unit as much as possible. I will attach some photos. The base or bed plate is very highly corroded. I have two questions about this. One regards the two labels on it. One says "A-2" and the other "91 705". Are these labels important? Given the high level of corrosion, do you think it is worth trying to remove the corrosion or should this part be replaced? Another questions is regarding the metal parts themselves. How is the metal finished? I assume it is not plated so what is the coating or finish? If I soak the corroded parts in rust remover, will they need to be re-finished? The pulleys on the type head carriage move freely although there is some surface rust. I have included some photos of the motor which I suppose moves the platen. It is seized and will not move by hand. The other motor, that I guess drives the carriage assembly, moves freely by hand. The motor in the print head also moves freely by hand. I have not further disassembled the platen assembly. This also seems to have a lot of rust and corrosion so I am wondering if this entire assembly needs to be replaced if possible.

Thanks,

Kevin

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[kphill01]

More pictures . . .

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[ProgBernie]

A happy new year!
A lot of work to be done. Good luck! The chassis plates were supposedly chromated (iron galvanised with zinc and then yellow chromated). If you want to restore them, I would try to blast clean them and then re-galvanise them, if you have the possibility to let it done.
The motor could be opened and cleaned.
For the small parts it could be a valid option to get chinese tumbler (vibration and/or rotary) to clean the parts. A magnetic tumbler with needles is more effective to clean off rust and dirt, but it is more costly. See https://radio-bastler.de/forum/showthread.php?tid=14749 for some details on tools to get excellent results.

[kphill01]

Ouch... that looks not good.
My suggestion would be to send you a working "machine" without the cover and base plate.
Or at least the parts that are absolutely not restorable.
I would guess shipping for these parts would be affordable unlike a complete machine with case.

[kphill01]

Hi Kevin,

I think Henning's suggestion makes the most sense - the cost of repairing what you have there makes almost no sense - even if you het all of the plated parts blasted, the original surface will still be pitted.

The stepper motors that have seized may just be bearings, though it is likely that the laminations on the rotor will have corroded, and this is causing the motor to be jammed (I have had this experience on some poorly stored video recorders)

Whatever route you choose, good luck with it - this is going to be a major project

[kphill01]

Hello, Henning and Sean. I understand. The solution with removing rust sounds very interesting and I would not mind trying that but I would have to invest in the equipment to do that. I have already tried removing rust from a plate or board (?) into which one of the PCB's slides (it stands vertically near the rear of the machine). I have soaked that part in some liquid rust remover. Part of it would still need to be blasted or scraped. The rust remover has also removed the coating or finish of the metal. I think I could find someone to galvanize metal parts but I do not know about chromating them. I do not have experience disassembling a motor and am willing to try but would not look forward to that. ;-) I wonder if I could still use the PCB's/electronic boards from this machine, in particular the "personality" board (?). The typing unit seems to be the main problem as well as perhaps the mains filter unit. Or, if someone would tell me what potting material was used which could be replaced I could try that. I have not yet tried to clean the PCB's. I will try to do that this weekend.

73

Kevin

[kphill01]

Hi Kevin

If you can find a plating shop that does Zinc Plating, then they will almost certainly be able to do Yellow Passivate on top of the Zinc - it is a standard process to put a hardened layer over the softer Zinc.

They may also have faster methods to remove rust.

Blasting is quick, and reasonably cheap, but on thin and small items, damage is a real possibility. there is also a process of electrolytic rust removal - I have tried this and it does work, though the process is slow.

I would say that the electronics could potentially live again - but starting from a known working position has to be easier

On the other hand, I fully understand why this would look like an interesting challenge - it's probably the same bug that has me sodding around with horrible electronic machines that spend more time broken than working

[kphill01]

I could try the electrolytic method to remove the rust; I see some information on that and I have or could easily get the items necessary. The one piece that is really, really bad is the base/chassis part. The rest have only light rust and I think they could be cleaned without lasting damage to the parts. Even with cleaning, my concern with the base plate in the photos is that it will have lost quite a lot of metal. However, in this piece I suppose that may not be (?) much concern since it is so thick. The motor *would* concern me.

One item I have not shown is the keyboard. It is dirty but I believe it can be cleaned OK.