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Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders. |
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16th Nov 2018, 8:56 pm | #1 |
Rest in Peace
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Heathkit OS1 scope voltages
I have a Heathkit OS1 scope with a sick mains transformer. I have the construction manual and circuit.
Does anyone have the HT and EHT voltages to aid in rewinding the transformer? This is a future project, with luck it will eventually get to the top of the pile. |
16th Nov 2018, 9:56 pm | #2 |
Dekatron
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Re: Heathkit OS1 scope voltages
Trevor, long ago (~1980) I had two of these (?) scopes taken from a skip.
Attached is a circuit diagram; I have a better copy, but it exceeds the file size limit. Do these look right? Somewhere, I may have a transformer. B
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16th Nov 2018, 10:13 pm | #3 |
Dekatron
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Location: Newcastle upon Tyne, Tyne & Wear, UK.
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Re: Heathkit OS1 scope voltages
Hi Trevor, mail me when you get round to doing this and I'll see if I have a used /tested transformer that will do in my collection. Is there much space in the chassis for a larger transformer?
Ed |
16th Nov 2018, 10:16 pm | #4 |
Octode
Join Date: Jan 2003
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Re: Heathkit OS1 scope voltages
That circuit is for a more sophisticated Heathkit scope. It's from an O-12, which was sold as a 'lab' scope as far as I remember.
Ron |
17th Nov 2018, 5:28 pm | #5 |
Octode
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Re: Heathkit OS1 scope voltages
I have these two, which I think are the right scope. I'm afraid there are still no voltages shown.
Colin. |
17th Nov 2018, 6:57 pm | #6 |
Octode
Join Date: May 2009
Location: Stevenage, Herts. UK.
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Re: Heathkit OS1 scope voltages
Page 27 of the manual gives 235Vac on the rectifier anodes and -700Vdc on CRT pin 8 (depending on brightness). No Vac into the stick, but Ed may be able to estimate this!
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17th Nov 2018, 8:07 pm | #7 |
Dekatron
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Location: Newcastle upon Tyne, Tyne & Wear, UK.
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Re: Heathkit OS1 scope voltages
Hi Gents, it is possibly a 250-0-250 for main Ht then a 350v overwind on one of the rect anode windings as the loading will only be low.
It would be possible to configure a voltage multiplier (tripler?) from one of the rect anodes. Ed |
17th Nov 2018, 9:04 pm | #8 |
Nonode
Join Date: Dec 2012
Location: Kirk Michael, Isle of Man
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Re: Heathkit OS1 scope voltages
I once had a TQ D43 with the highest voltage winding of the transformer open circuit.I did exactly what Ed suggests and made up a multiplier (quintupler?) which worked perfectly. I had a willing customer who knew the score, and got a good working calibrated scope at a price he could afford. 35 years ago, I wonder if he still has it?
Les. |
17th Nov 2018, 9:13 pm | #9 | |
Octode
Join Date: Jan 2012
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Re: Heathkit OS1 scope voltages
Quote:
https://frank.pocnet.net/sheets/198/3/3AFP1.pdf you will see that the maximum final anode voltage for the 3AFP1 crt is 1.0 kV. There is some more data on the crt, too. I hope it helps. Colin. |
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18th Nov 2018, 1:07 am | #10 |
Rest in Peace
Join Date: Apr 2011
Location: Matlock, Derbyshire, UK.
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Re: Heathkit OS1 scope voltages
Thanks for the information. I will put it to one side for a time and will rewind a simple battery charger as my first mains transformer I have wound coils for geetah pick ups, 30000 turns for a slave clock solenoid and a few hundred turns for a low tension ignition coil (1900 Mercedes engine).
The transformer has the flu as it is sweating so will not give correct voltages. I do not think that a couple of paracetamol will help. More investigation needed. It is just an idea at the moment, I thought I might get rid of the primary taps, use a single 250V winding with a coule of diodes to make a bridge and use a separate winding doubled for the EHT, thus balancing the series capacitors. No taps should be easier to make. |