Needing transformer for goldstar oscilloscope

[nzoomed]

Needing Line output transformer for goldstar oscilloscope

Any help would be great thanks.
My Line output transformer for the CRT has blown in my Goldstar OS-7020A Oscilloscope. part number on the transformer and in the service manual is 622-017-9 and description is HVT-3D(4011). thats all the info i have, the transformer looks like a small black cuble about 1 inch square roughly.
Thanks for any help leading to a compatible or similar transformer.

 

[Nigel Goodwin]

I would suggest the only way is as a spare part from Goldstar or a spares distributor.

 

[nzoomed]

im not sure if its a goldstar part or not

but the suppliers here cant get one, its possible that i may be able to adapt a flyback transformer to suit it, but would have to find a small one and rewire it without the diodes, surley there are other transformers of the same type that would do a similar job. thanks if anyone has more info

 

[nzoomed]

no luck finding it yet, anyone else have any ideas? would a photo be of any help, or is the model number and description enough? it is NOT a flyback, the diodes are on the PCB not on the transformer.

 

[Nigel Goodwin]

You've already had the answer, wishing it wasn't so isn't going to make any difference - it's almost certainly specifically made for Goldstar, and will only be available through them.

 

[nzoomed]

the suppliers who i got it from cant get me one

but there is no goldstar office in New Zealand, so its not much use asking the suppliers here, why make a product that cant use standard parts? its pathetic, they know its technicians that use this sort of equipment, if they cant supply parts i think its bad on their part.

 

[mvs sarma]

but there is no goldstar office in New Zealand, so its not much use asking the suppliers here, why make a product that cant use standard parts? its pathetic, they know its technicians that use this sort of equipment, if they cant supply parts i think its bad on their part.

Perhaps I don't expect Nigel to add another reply that you may have to contact the manufacturers, may be Korea or any other country, and try placing an order and import by paying duties.
Alternatively any T&M equipment repairer would know methods of how to go about in such cases. you may find some local services in your country and get it done by payment if you don't feel like importing a spare part.


look up to north and you might find Korea's helping you.

 

[Nigel Goodwin]

but there is no goldstar office in New Zealand, so its not much use asking the suppliers here, why make a product that cant use standard parts? its pathetic, they know its technicians that use this sort of equipment, if they cant supply parts i think its bad on their part.

Did you buy the scope in New Zealand?, if so there's presumably a service system in place 'somewhere', but probably only authorised service agents will have access to spares.

An EHT transformer in a scope (or indeed anything else) is a specially made part for a specific model, there never have been any 'standard' parts.

 

[nzoomed]

the agents for goldstar said they used to

be able to get in parts from them, but not anymore, if worst comes to the worst i will try and contact korea, its now LG electronics anyway. however i have been advised it shouldnt be too much trouble to make it take a flyback by a few mods, i will try and find more specs on the transformer, if i can find something that puts out the same voltage, it should work fine

 

[mvs sarma]

be able to get in parts from them, but not anymore, if worst comes to the worst i will try and contact korea, its now LG electronics anyway. however i have been advised it shouldnt be too much trouble to make it take a flyback by a few mods, i will try and find more specs on the transformer, if i can find something that puts out the same voltage, it should work fine

I moderate my opinion towards a replacement of the scope as it is just 20MHz one.

to purchase another secondhand one may be cheaper than searching for the spare part and the transportation of same to reach you. I was watching few ads on e-bay -- better ones like 50 or100MHz at a reasonable price.

 

[nzoomed]

thats probably what i will do

if i dont get anywhere, however, it is far better quality than alot of the cheap chinese scopes i see even if they are 100mhz, ive never really needed to go over 20mhz

 

[Hero999]

Have you checked eBay?

You might be able to buy a new scope for cheaper than the cost of repairing it or buy a broken scope with a working transformer for next to nothing.

 

[nzoomed]

I havnt found anything on ebay yet

its probably will be cheaper to buy a new scope, but i will try and see if i can rewind it, it looks like its not that hard to rewind, here is the photos of it, to see if anyone knows if they have seen one:
**broken link removed**
**broken link removed**

 

[audioguru]

My 'scope was an American kit, is about 43 years old and still works fine.

I worked with some Goldstar telephone systems in 1980 and they had the worst circuits, pcbs and soldering that i have ever seen.
No wonder they changed their name!

My monitor is an LCD Samsung made in Korea and it works fine so they learned how to make things properly recently.

 

[mvs sarma]

Hai, Nzoomed,
After observing the photos, I feel hopefully that the transformer may not be faulty. please have a check at other components at the voltage multiplier at the output of the transformer. some times either a diode or a capacitor might be responsible and we may suspect the transformer. try removing ONE limb of each component and have a thorough check with Multimeter for any leakage.

 

[nzoomed]

Hi there, unfortunatley it is faulty

i rewound some of the heavier windings, that had got hot, and were starting to burn, and the inner windings, that i think are 0.05 gauge, are extremley fine, finer than human hair, those need replacing, it had broken underneath, and i soldered it back to the leads, but still read open circuit with my multimeter, so i am going to rewind it, and i should be back in order! unless i have other problems.

 

[mvs sarma]

i rewound some of the heavier windings, that had got hot, and were starting to burn, and the inner windings, that i think are 0.05 gauge, are extremley fine, finer than human hair, those need replacing, it had broken underneath, and i soldered it back to the leads, but still read open circuit with my multimeter, so i am going to rewind it, and i should be back in order! unless i have other problems.

Rewind it , but with precaution that there is no possibility to for short circuit across wires of layers of the same section.

 

[nzoomed]

ive tried rewinding, buts its hopeless

i dont know how many windings there are, and as i count, it kept breaking off, and i could not find the wire again, i will just have to guess, and see what happens

 

[mvs sarma]

i dont know how many windings there are, and as i count, it kept breaking off, and i could not find the wire again, i will just have to guess, and see what happens

Yes. you have landed in a NO RETURN path. You have to hod your patience and some how complete it, as no one else, including a professional winder could handle it at this stage.

If your problem is with varnish sticking, try soaking it with some thinner (BEWARE, THE BOBBIN SHOULD NOT BE EFFECTED by the same thinner-- so have a test first at a small area on the bobbin) and handling may be easy with rubber gloves as used by surgeons to take care of your fingers.

 

[nzoomed]

YAY! ive fixed it!

It actually works! i cant beleive it! i took off all the windings, as i could not count them, but at a rough guess, its around 200 on each segment, as i filled the bobbin up to where the wire used to be, and i even had to guess the centre tap on the first winding at around 100! ill post photos ASAP, i was expecting it to blow up!