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Old 17th Nov 2019, 10:42 am   #1
WaveyDipole
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Default Damaged vintage variac

I recently acquired a vintage variac on eBay. Being rated at 8 amperes, it is quite a large heavy item. According to the seller, the variac was tested and confirmed in working order prior to dispatch, but it would seem that due to inadequate packaging, it was damaged in transit with RM.

The variac seems mostly intact, i.e. coil, handle, faceplate and other plastic/Bakelite parts seem undamaged, however the hexagonal base of the chassis has a large bend one of its corners. The variac has three evenly spaced pillars between the bottom and top, and the bend is to one of the in-between corners and stretches almost all the way between these pillars. Thankfully the damage did not affect the coil, however, the armature appears to be seized. Since the seller assures me that the item was tested before being sent out, I have to assume that the seizure is on account misalignment due to the damage although this is not immediately obvious from a visual examination. Moreover, without disassembly I cannot be certain whether there is any further internal damage or whether the seizure is simply down to disuse and age.

I am therefore trying to weigh up the potential risk of repair. I believe that the bend in the chassis could possibly be straightened after disassembly, but I am still concerned about the alignment. Since I am currently negotiating settlement with the seller, I would prefer not to post too many details or photos and have not done anything with the unit nor do I intend to until the matter is settled. As matters stand, the likelihood is that I will end up returning the item and eBay will most probably support my case, but if there is a possibility that the variac could be easily repaired, then I might consider accepting a partial refund. The offer would have to be very compelling for me to do so. On the other hand, if the risk is too great that the shaft will no longer align or of further internal damage, then my position is obvious.

Anyone had experience of trying to repair a variac with a damaged chassis and could provide any insight as to how easy/difficult it was to repair?

Last edited by WaveyDipole; 17th Nov 2019 at 11:02 am.
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Old 17th Nov 2019, 10:50 am   #2
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Default Re: Damaged vintage variac

In my experience "most" variacs ( generic term) are made up from either diecast aluminium, or worse monkey metal AKA diecast zinc. Neither will like you "straightening" it. I have dropped a real English Variac, and it was aluminium. BUT it was what I call "cold cast".

Very accurate casting, but NOT malleable at all. I ended up cracking the bit I damaged and I thought it was lost. A VERY talented welder bent it back to shape and TIG welded the damage I created.

I would NOT go in, hammer and tongs, so to speak. That's what I did. Check out a motorcycle mechanic, one that REALLY knows his trade.

Just my take

Joe
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Old 17th Nov 2019, 12:32 pm   #3
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Default Re: Damaged vintage variac

As Joe says, if the "chassis" is any form cast material then any attempt at straightening it is likely to result in it cracking. Chances are the shaft and bearings may be damaged too. I have successfully straightened shafts, but it required a lathe, dial gauge and hydraulic press.

I'd only tackle the job if you have nothing to lose.
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Old 17th Nov 2019, 1:09 pm   #4
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Default Re: Damaged vintage variac

I'm guessing that this is one of those big heavy Lyons Zenith Variacs with a skeleton frame in which case the whole frame is likely to be distorted to a greater or lesser extent. Very difficult to correct I suspect with a distinct risk of cracking the castings.

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Old 17th Nov 2019, 1:25 pm   #5
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Default Re: Damaged vintage variac

Send it back for a full refund and seek out another.
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Old 17th Nov 2019, 2:21 pm   #6
WaveyDipole
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Default Re: Damaged vintage variac

Yes it does have a skeleton frame and my idea was to dismantle and remove the base and sandwich it between something sturdy in a vice and gradually flatten, although I hadn't really thought about what type of metal the chassis is made from. Having read the comments, I tried scraping a little in an inconspicuous place on the bottom with a small craft scalpel and the material is soft enough to be cut, so I it is likely to be aluminium or some sort of monkey metal type alloy. I agree that such metals tend to not like the stress of being straightened, so I guess that puts a repair into a "very risky" category, and that is before one considers the alignment and possible damage to the bearings. Should the shaft or frame be distorted, I don't have a lathe or any other specialist tools or skills to machine parts to make corrections.

Thank you for the comments. They have been very helpful to me in evaluating the repair risk and making a decision in the matter. My mind is now made up to accept nothing less than a full refund.

Last edited by WaveyDipole; 17th Nov 2019 at 2:30 pm.
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Old 17th Nov 2019, 2:44 pm   #7
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Default Re: Damaged vintage variac

I agree, full refund is the way to go. If the seller doesn't want it returning then you could have a go at repairing it as you have nothing to lose apart from some time.

Without photos etc it is difficult to comment, but is there any way things could be packed out with washers or whatever to get it reasonably back to alignment without straightening the casting?
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Old 17th Nov 2019, 3:04 pm   #8
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Default Re: Damaged vintage variac

Probably not relevant now but if the Variac is like the smaller Lyons Zenith designs there aren't really any bearings as such. The aluminium control shaft simply rotates inside a tube made of a non-conductive fibrous material. It's possible of course that the shaft is now slightly bent as mentioned in an earlier post.

Alan

Additional Info: To be more accurate, the shaft and the fibrous tube are clamped together and the entire assembly rotates inside a central metal tube. I've just checked mine!

Last edited by ajgriff; 17th Nov 2019 at 3:17 pm. Reason: Additional Comment
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Old 17th Nov 2019, 3:22 pm   #9
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Default Re: Damaged vintage variac

Paul, that's a good idea about the washers. Thanks. I appreciate what you mean regarding photos, but I wasn't sure what the policy is on such matters when a claim is ongoing. I didn't want to risk legally prejudicing the matter although I did inform the seller that I would be seeking advice regarding the viability of repair. I now have to wait and see how things turn out, but if it ends up with the seller not wanting it returned then your idea may certainly be worth a try if it comes to it.
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Old 17th Nov 2019, 7:00 pm   #10
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Default Re: Damaged vintage variac

Ebay I think would cover you if the seller refuses to help.
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Old 17th Nov 2019, 9:06 pm   #11
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Default Re: Damaged vintage variac

The fact that it bent rather than crumbled is promising. Aluminium castings of good quality can be heated and worked back into shape. I do it with propane torch, anvil and a selection of hammers and a reference straight edge. It's good to have the TIG there to do a rescue job if there is a crack.

Motorcyclists and alloy wheels on cars provide a steady source of work for those with forging and TIG welding skills. So there is likely to be a firm in your area which could help. It's quite remarkable what can be put back together given plenty of time and some experience. The sources of the skills may be OT for this forum, but their application to electronic things can be very valuable. I've repaired broken castings for amateur radio antenna rotators, made aluminium cabinetry for radio gear.

A photo of the damage would help a lot in assessing possibilities.

David
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Old 17th Nov 2019, 9:24 pm   #12
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Default Re: Damaged vintage variac

The seller can probably obtain compensation from RM. Due to a wish to reduce postal charges and the need to get a sale, packaging can be more of a compromise than one would wish for. No packaging is bomb proof and the actions of some drivers have to be seen to be believed, although 90% are careful. I sent a telephone once that was damaged after being put over a high fence. I got the postage plus sale value back and the buyer kept the damaged item.
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Old 17th Nov 2019, 9:31 pm   #13
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Default Re: Damaged vintage variac

Quote:
Originally Posted by WaveyDipole View Post
Paul, that's a good idea about the washers. Thanks. I appreciate what you mean regarding photos, but I wasn't sure what the policy is on such matters when a claim is ongoing. I didn't want to risk legally prejudicing the matter although I did inform the seller that I would be seeking advice regarding the viability of repair. I now have to wait and see how things turn out, but if it ends up with the seller not wanting it returned then your idea may certainly be worth a try if it comes to it.
I agree that it is best to hold off posting photos until the case is resolved, very sensible approach. The information you have now confirms that a full refund would be the best outcome.

Once it's resolved, if you get to keep it, then post your own photos (none of the originals from the listing) and we can see whether there's a way of making it usable.
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Old 30th Nov 2019, 10:39 pm   #14
WaveyDipole
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Default Re: Damaged vintage variac

Well I waited the 8 days or so before I could ask eBay to step in, during which some messages were exchanged, and a further 5 days for eBay to deal with matters. Today they have closed the matter and issued a refund. Since there was no indication as to what I was to do with the item, I asked them and was advised that I am under no obligation to return it, but the seller could still request return and provide return postage. As a result, I think it seems reasonable to perhaps allow another week for the seller to get in touch and provide return postage, but although the refund has been sorted, the situation as regards does, for the present, still seem a little unclear.

Last edited by WaveyDipole; 30th Nov 2019 at 11:00 pm.
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Old 1st Dec 2019, 10:18 pm   #15
MotorBikeLes
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Default Re: Damaged vintage variac

Ebay will offer to send the seller a retutn delivery label, which he asks you to use. When the postal system tells Ebay it (the variac in this case) is delivered, then Ebay charge the Seller for the return postage label. If he does not use it, he does not get charged, and as time goes by, you are free to dispose of the goods.
That is my understanding.
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Old 2nd Dec 2019, 8:24 am   #16
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Default Re: Damaged vintage variac

No further discussions about eBay, the seller or the complaint now please. It is pushing the forum eBay rules a bit already.

Discussions about the repairs if/when this happens are fine of course. It will be interesting to see if it is salvageable.

Thank you.
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Old Today, 12:27 pm   #17
WaveyDipole
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Default Re: Damaged vintage variac

OK, I think it is time to move on so I have started to dismantle the variac to see whether it can be salvaged. I got as far as removing the knob and dial and the retaining nuts from the top plate. Removing the handle was a matter of removing the two retaining grub screws set unto the metal collar and through the plastic/Bakelite to grip the shaft. I cannot remove the two screws that are set into the plastic handle itself and so at present cannot remove the handle from the shaft. It is rather loose and would want to make sure that it is firmly attached when I re-assemble. I am hoping that a little WD40 will do the trick.

Should the top plate now slide off? Before tapping it with a hammer or anything else I want to ask for advice as to what to do next and where to apply any leverage (if necessary - I was hoping not) as I don't want to risk damaging anything.

I did notice that there are a couple of screws securing the rotor/wiper assembly, I think, to some part of the centre Bakelite/plastic shaft or spindle, but am still a little unclear as to whether the rotor is meant to come off together with the top plate or whether this is a separate component.

The first photo is the top view and shows just how dirty it is. The next one shows the rotor and wiper assembly which is seized. The contact bridge can clearly be seen to the right and also in the 3rd photo, but that wire braid would surely catch it? Perhaps it doesn't rotate past that point. I won't know until I manage to free it. The fourth and fifth photos show the base. It looks a bit cleaner, but the bend can clearly be seen. I was hoping that I can remove the base but this seems to require disassembly from the top side.

If anyone has an idea as to how I can remove the top, it would be appreciated.
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Last edited by WaveyDipole; Today at 12:33 pm.
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Old Today, 1:03 pm   #18
ajgriff
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Default Re: Damaged vintage variac

This is a bit of a guess based on the smaller Lyons Zenith Variacs but is there some kind of clip or collet at the bottom of the central shaft when viewed from underneath? On the smaller ones it's just a circlip with a diameter of about 3/4 inch. Once removed, the shaft (complete with rotor assembly and control knob) can be withdrawn. Makes the whole dimantling process much easier. The attached diagram shows the construction of the Lyons Zenith V-5 Duratek Series (2-2.5 Amp) which might help. The drawing on the right is a view of the base and shows the circlip mentioned above.

Alan
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Old Today, 2:14 pm   #19
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Default Re: Damaged vintage variac

Looking at your photos again it looks like you've already withdrawn the shaft so I hope I haven't confused matters. The central insulating sleeve seems to be still in place and this is the component which is secured by circlips at both ends on the smaller version. Hope the diagram helps a bit anyway. I suspect that you will end up with a very worthwhile working Variac.

Alan
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Old Today, 2:29 pm   #20
WaveyDipole
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Default Re: Damaged vintage variac

Quote:
Originally Posted by ajgriff View Post
This is a bit of a guess based on the smaller Lyons Zenith Variacs but is there some kind of clip or collet at the bottom of the central shaft when viewed from underneath? On the smaller ones it's just a circlip with a diameter of about 3/4 inch. Once removed, the shaft (complete with rotor assembly and control knob) can be withdrawn. Makes the whole dimantling process much easier. The attached diagram shows the construction of the Lyons Zenith V-5 Duratek Series (2-2.5 Amp) which might help. The drawing on the right is a view of the base and shows the circlip mentioned above.
Alan
Thanks for that. I realised that I had not provided any information about this variac. It is indeed a 'Zenith Variac Type 100Ω' with an input of 240V and output of 0-270V rated at 8A, 2.1kVA. It also has the "Duratrack" branding on the connector plate.

In the meantime I also found a video related to a repair of an almost identical unit:

https://www.flameport.com/equipment_...riac/index.cs4

The author's unit is in a case and the variac is very much cleaner! He skips a bit during the dismantling process so I can't quite tell whether he removes only the top three nuts, or whether there is more involved. He also removes the retaining screws for the connector plate. I had unscrewed the top screws attached to the top plate, but not the bottom ones. I probably also need to disconnect the wiper connecting wire which I will do next.

From the video it does look like the top plate complete with the rotator/wiper assembly and shaft should just withdraw from remaining chassis. The author seemed able to quite easily move the wiper by hand as well as remove the assembly with very little force, something which I am at present unable to do. It seems that the centre shaft should easily come out of the base, but at present it seems firmly stuck. I imagine that this is probably what is keeping it in place. There does seem to be a bit of dirty run-off around the shaft at the base so it might seizure caused by dirt/sediment or maybe a distortion of the metal caused by the dent, although the centre section does look relatively undisturbed. The question is, whether there anything that can be done to free it? I tried tapping both the top plate and the shaft at the base with the back end of a large screwdriver but it doesn't seem to want to budge. From what I can tell though, nothing appears to be be cracked.

Last edited by WaveyDipole; Today at 2:36 pm.
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