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Zenith 7H920 Restoration
#59

Thanks Mike!


As for the alignment, I was able to complete it.
There were several factors.

1. My SG output was unreliable: this protection device I made years ago from two BNC connetors was making intermittent contact. I think that 0603 50 Ohms resistor either cracked or disconnected.

2. I used a 1:1 scope probe (it measures 280 Ohm end-to-end, so I thoughgt it would protect at least some) to feed the signal to the Limiter grid.

3. I used 2M resistor in series with the DMM Red lead, and I twisted the leads to minimize the pickup. I intend to manufactire a shielded probe for it.

So, the voltage immediately became negative (as it should) and I was able to peak the Lug 6 and minimize (no it is not zero but a few mV, and I found the minimum) the Lug 3.


Seems to work fine.




Now to the rectifier. I was worrying about the temp rize, but I was assessing it with my finger and thermocouple. It showed 150F.
I looked at the datasheet of a similar resistor, whose thermal resistance is about 56 K/W.
I have exactly 6.25V across that 82 Ohm resistor.
This is 0.48W

This should give me 26.7K temp rise, and the ambient there is about 19C, so it is 46C or 115F. 115F is still very uncomfortable to touch and will burn over time.

It is possible my resistor Thermal resistance is a bit higher (the datasheet is YAGEO) and mine is some noname bought through eBay.

But. The good news is, even 150F is safe temp for wires around; they should be rated at least for 100C (212F).

So I might just leave it be.

People who do not drink, do not smoke, do not eat red meat will one day feel really stupid lying there and dying from nothing.


Messages In This Thread
Zenith 7H920 Restoration - by morzh - 12-17-2025, 10:03 PM
RE: Zenith 7H920 Restoration - by MrFixr55 - 12-17-2025, 11:14 PM
RE: Zenith 7H920 Restoration - by radiorich - 12-18-2025, 01:01 AM
RE: Zenith 7H920 Restoration - by Arran - 12-18-2025, 07:12 AM
462ron - by 462ron - 12-18-2025, 08:27 AM
RE: Zenith 7H920 Restoration - by RodB - 12-18-2025, 12:02 PM
RE: Zenith 7H920 Restoration - by morzh - 12-18-2025, 12:31 PM
RE: Zenith 7H920 Restoration - by rfeenstra - 12-19-2025, 12:54 AM
RE: Zenith 7H920 Restoration - by MrFixr55 - 12-19-2025, 03:02 PM
RE: Zenith 7H920 Restoration - by Arran - 12-19-2025, 03:37 PM
RE: Zenith 7H920 Restoration - by Arran - 12-19-2025, 07:51 PM
RE: Zenith 7H920 Restoration - by David - 12-20-2025, 09:43 AM
RE: Zenith 7H920 Restoration - by morzh - 12-20-2025, 01:30 PM
RE: Zenith 7H920 Restoration - by morzh - 12-20-2025, 08:26 PM
RE: Zenith 7H920 Restoration - by David - 12-20-2025, 08:51 PM
RE: Zenith 7H920 Restoration - by morzh - 12-20-2025, 10:50 PM
RE: Zenith 7H920 Restoration - by MrFixr55 - 12-21-2025, 12:13 AM
RE: Zenith 7H920 Restoration - by morzh - 12-21-2025, 11:01 AM
RE: Zenith 7H920 Restoration - by morzh - 12-21-2025, 10:31 PM
RE: Zenith 7H920 Restoration - by morzh - 12-22-2025, 09:33 PM
RE: Zenith 7H920 Restoration - by Paul Philco322 - 12-22-2025, 09:42 PM
RE: Zenith 7H920 Restoration - by morzh - 12-22-2025, 10:51 PM
RE: Zenith 7H920 Restoration - by Arran - 12-23-2025, 04:26 AM
RE: Zenith 7H920 Restoration - by MrFixr55 - 12-23-2025, 08:35 AM
RE: Zenith 7H920 Restoration - by morzh - 12-23-2025, 02:25 PM
RE: Zenith 7H920 Restoration - by David - 12-23-2025, 07:14 PM
RE: Zenith 7H920 Restoration - by MrFixr55 - 12-23-2025, 08:30 PM
RE: Zenith 7H920 Restoration - by morzh - 12-23-2025, 09:04 PM
RE: Zenith 7H920 Restoration - by morzh - 12-24-2025, 08:18 PM
RE: Zenith 7H920 Restoration - by morzh - 12-25-2025, 11:43 AM
RE: Zenith 7H920 Restoration - by morzh - 12-26-2025, 09:54 AM
RE: Zenith 7H920 Restoration - by morzh - 12-30-2025, 06:07 PM
RE: Zenith 7H920 Restoration - by Arran - 12-30-2025, 07:28 PM
RE: Zenith 7H920 Restoration - by morzh - 12-30-2025, 07:32 PM
RE: Zenith 7H920 Restoration - by Arran - 12-30-2025, 10:49 PM
RE: Zenith 7H920 Restoration - by RodB - 12-31-2025, 11:55 AM
RE: Zenith 7H920 Restoration - by Vlad95 - 12-31-2025, 01:43 PM
RE: Zenith 7H920 Restoration - by RodB - 12-31-2025, 04:30 PM
RE: Zenith 7H920 Restoration - by David - 12-31-2025, 07:03 PM
RE: Zenith 7H920 Restoration - by morzh - 12-31-2025, 09:12 PM
RE: Zenith 7H920 Restoration - by morzh - 12-31-2025, 09:21 PM
RE: Zenith 7H920 Restoration - by Vlad95 - 12-31-2025, 09:44 PM
RE: Zenith 7H920 Restoration - by morzh - 12-31-2025, 10:48 PM
RE: Zenith 7H920 Restoration - by Vlad95 - 12-31-2025, 11:26 PM
RE: Zenith 7H920 Restoration - by morzh - 12-31-2025, 11:48 PM
RE: Zenith 7H920 Restoration - by Vlad95 - 01-01-2026, 12:03 AM
462ron - by 462ron - 01-01-2026, 09:16 AM
RE: Zenith 7H920 Restoration - by RodB - 01-01-2026, 11:01 AM
RE: Zenith 7H920 Restoration - by RodB - 01-01-2026, 12:10 PM
RE: Zenith 7H920 Restoration - by morzh - 01-01-2026, 12:28 PM
RE: Zenith 7H920 Restoration - by Vlad95 - 01-01-2026, 01:37 PM
RE: Zenith 7H920 Restoration - by RadioSvit - 01-01-2026, 03:57 PM
RE: Zenith 7H920 Restoration - by RodB - 01-01-2026, 03:57 PM
RE: Zenith 7H920 Restoration - by Vlad95 - 01-01-2026, 04:10 PM
RE: Zenith 7H920 Restoration - by morzh - 01-01-2026, 05:52 PM
RE: Zenith 7H920 Restoration - by morzh - 01-01-2026, 05:54 PM
RE: Zenith 7H920 Restoration - by morzh - 01-01-2026, 05:57 PM
RE: Zenith 7H920 Restoration - by KCMike - 01-02-2026, 02:55 PM
RE: Zenith 7H920 Restoration - by morzh - 01-02-2026, 07:08 PM
RE: Zenith 7H920 Restoration - by morzh - 01-02-2026, 10:44 PM
RE: Zenith 7H920 Restoration - by radiorich - 01-03-2026, 01:07 AM
RE: Zenith 7H920 Restoration - by morzh - 01-03-2026, 11:47 AM
RE: Zenith 7H920 Restoration - by morzh - 01-03-2026, 04:01 PM
RE: Zenith 7H920 Restoration - by morzh - 01-03-2026, 05:20 PM
RE: Zenith 7H920 Restoration - by Vlad95 - 01-03-2026, 05:26 PM
RE: Zenith 7H920 Restoration - by morzh - 01-03-2026, 05:44 PM
RE: Zenith 7H920 Restoration - by radiorich - 01-03-2026, 10:53 PM
RE: Zenith 7H920 Restoration - by morzh - 01-03-2026, 11:49 PM
RE: Zenith 7H920 Restoration - by morzh - 01-03-2026, 11:53 PM
RE: Zenith 7H920 Restoration - by morzh - 01-04-2026, 07:29 PM
RE: Zenith 7H920 Restoration - by MrFixr55 - 01-04-2026, 09:56 PM
RE: Zenith 7H920 Restoration - by morzh - 01-04-2026, 10:04 PM
RE: Zenith 7H920 Restoration - by radiorich - 01-04-2026, 10:09 PM
RE: Zenith 7H920 Restoration - by morzh - 01-04-2026, 10:17 PM
RE: Zenith 7H920 Restoration - by radiorich - 01-04-2026, 11:34 PM
RE: Zenith 7H920 Restoration - by MrFixr55 - 01-05-2026, 06:31 AM
RE: Zenith 7H920 Restoration - by radiorich - 01-05-2026, 09:13 AM
RE: Zenith 7H920 Restoration - by morzh - 01-05-2026, 10:15 AM
RE: Zenith 7H920 Restoration - by morzh - 01-05-2026, 01:14 PM
RE: Zenith 7H920 Restoration - by morzh - 01-05-2026, 04:16 PM
RE: Zenith 7H920 Restoration - by morzh - 01-11-2026, 07:50 PM
RE: Zenith 7H920 Restoration - by MrFixr55 - 01-11-2026, 10:12 PM
RE: Zenith 7H920 Restoration - by morzh - 01-11-2026, 10:35 PM
RE: Zenith 7H920 Restoration - by DaleHCook - 01-12-2026, 10:31 AM
RE: Zenith 7H920 Restoration - by morzh - 01-12-2026, 02:30 PM
RE: Zenith 7H920 Restoration - by DaleHCook - 01-12-2026, 03:23 PM
RE: Zenith 7H920 Restoration - by David - 01-15-2026, 05:30 PM
RE: Zenith 7H920 Restoration - by morzh - 01-15-2026, 05:44 PM



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