[Heathkit] SB 200 with Harbach mods has problems

[Carl]

To be honest John, the only issue Ive had with that assembly has been a 
cockpit problem. Its real easy to get the resistors and wires mixed up as 
you say the documentation sucks, especially when your tired and in a hurry.

Ive probably installed 30-40 over the years during 6M conversions and some 
regular repairs.

A screwdriver blade will tell you if there is some HV after shutting power 
off and counting to 10. BTW, the 6KV Fluke probe regularly shows up on 
Fleabay.

Carl
KM1H

.
----- Original Message ----- 
From: "John King" <k5pgw at yahoo.com>
To: <Heathkit at mailman.qth.net>
Sent: Sunday, May 09, 2010 1:00 PM
Subject: [Heathkit] SB 200 with Harbach mods has problems


>I have an SB 200 that the Harbach power supply upgrades (?) have been 
>installed in and it developed a problem where R8 burned and after 
>replacement, the multi-meter reads zero in all positions with only a SLIGHT 
>kick when switched to plate and high voltage then instantly returns to zero 
>after the slight kick.
>
> When the multi-meter is placed in the "plate" position and the relay is 
> energized, the meter plate current position PEGS but there is no 
> indication from sound of tubes pulling current. It is believed that this 
> might be a meter multiplier problem. When the relay is energized by 
> grounding the relay there is NO meter indication in the Grid , HV, or 
> relative output positions.
>
> I am in Montana for the summer and have ONLY a multimeter (Fluke) with me 
> and the maximum voltage it will read is about 1000 volts. I find the 
> documentation from Harbach to be confusing.
>
> If you have had serious trouble shooting experience with the SB 200 with 
> Harbach mods in power supply, I would greatly appreciate the benefit of 
> your knowledge and experience. I am not sure that installation of the 
> Harbach power supply rectifier board is a great idea. What do you suggest 
> be done with very limited test gear? Your help will be appreciated. 73, 
> John, K5PGW
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> about 1800 vdc in the plate current position, not in the plate voltage 
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