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Old 20th Feb 2024, 2:37 pm   #1
lloydwells
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Default Frame blocking VDR problem.

OK so I'm currently working on a Danish made Always Herkules TV2361 it's a 23" set using a 110° tube the TV works however it has an audible ticking I've got this down to being something around the frame output transformer or frame blocking transformer this tv uses Early 1960s transformers and deflection unit by Philips see attached pictures. The diagram shows a Philips VDR part number VD9010 and a 1.2K 1 watt resistor across the primary of the frame blocking transformer this had had another incorrect VDR bodged in at some point and it's dead. I cannot find any info to help work out a replacement for this Philips VD9010 and sort this ticking i would point out that pin 5 and 6 of the Pcl82 feeding the transformer were arcing across the valve base I replaced the base same old ticking. Any help gratefully recieved.
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Old 20th Feb 2024, 4:08 pm   #2
dazzlevision
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Default Re: Frame blocking Vdr problem

The VDR you refer to is connected across the primary of the frame output transformer.

In the 1960s, a commonly used Philips/Mullard VDR in the UK across the primary of the frame output transformer was type E298ED/A258. This was a rod type VDR with axial leads and a green marking at one end. There was no series resistor.
The frame output valve was invariably a PCL85/PCL805.
If you are unable to find a good VD9010, this one might be worth a try.

Last edited by dazzlevision; 20th Feb 2024 at 4:14 pm.
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Old 21st Feb 2024, 2:30 am   #3
Maarten
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Default Re: Frame blocking VDR problem.

Unfortunately I can't read the datasheet. 2 back to back zenerdiodes of the right voltage might work.
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Old 21st Feb 2024, 11:59 am   #4
Marconi_MPT4
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Default Re: Frame blocking VDR problem.

Very brief data from book, Philips Components For Radio TV and Audio 1960, page 27.

Looks as if VD 9010 is characterised by passing 60 to 120uA at 100V. No information on the delta change for higher voltage. Maximum power dissipation is 0.5W for disc type and working temperature 150°C max.

More detailed information might be found on data sheet EP1526.

Rich
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Old 21st Feb 2024, 4:16 pm   #5
Welsh Anorak
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Default Re: Frame blocking VDR problem.

Not something I know anything about I have to admit, but this was in my drawer of themistors/VDrs. Is it what you're talking about?
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Old 21st Feb 2024, 4:27 pm   #6
dazzlevision
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Default Re: Frame blocking VDR problem.

Quote:
Originally Posted by Welsh Anorak View Post
Not something I know anything about I have to admit, but this was in my drawer of themistors/VDrs. Is it what you're talking about?
Yes, that’s the one used in UK made sets of the 1960s or its PCB equivalent.
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Old 21st Feb 2024, 4:36 pm   #7
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Default Re: Frame blocking VDR problem.

The function of the VDR across the primary of the output transformer is to partially suppress the positive going flyback pulse, but not too much as to impair the frame retrace characteristic. Removal of the VDR might cause damage to the transformer.
The energy of the flyback part of the scanning waveform must be same as the forward scanning part.
A diode clamp might be a possible solution. Clip the peak value of the flyback pulse.

DFWB.
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Old 21st Feb 2024, 5:28 pm   #8
Maarten
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Default Re: Frame blocking VDR problem.

Closest to original, would be a back-to-back zener diode clamp, or a bidirectional transil. Maybe 120V 5W? Just guessing from the few data we have.
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Old 21st Feb 2024, 5:48 pm   #9
FERNSEH
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Default Re: Frame blocking VDR problem.

From the Pye 169 manual.
The sawtooth waveform at the anode of the pentode section of the PCL85.
Note the amplitude of the flyback pulse, 700volts and that's with a VDR across the primary of the transformer.
The Herkules TV2361 under discussion has a 110degree deflection system so it's likely the waveform will be similar to that shown in the attachment.

DFWB.
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Old 21st Feb 2024, 6:16 pm   #10
Welsh Anorak
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Default Re: Frame blocking VDR problem.

If the VDR in post #5 is any use to the OP it's yours FOC. PM me if you'd like it.
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Old 22nd Feb 2024, 10:04 am   #11
lloydwells
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Default Re: Frame blocking VDR problem.

Welsh anorak I've actually found some for sale 10 for £4 seemed cheap enough but thanks for the offer.
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