[Heathkit] Heath Hm 102 watt meter questions

[Carl]

All germanium diodes have poor reverse performance and it gets worse with 
age. Trying to match replacements forward conduction without a large supply 
is an exercise in frustration. A modern Schottky such as the 1N5711 will 
have almost the same sensitivity (point of conduction) as the germanium but 
with virtually no leakage. These are very cheap at Mouser and elsewhere.

Carl
KM1H

----- Original Message ----- 
From: "John King" <k5pgw at yahoo.com>
To: <heathkit at mailman.qth.net>
Sent: Wednesday, July 06, 2011 9:51 PM
Subject: [Heathkit] Heath Hm 102 watt meter questions


>
>
>
>
> I own several  Heath HM 102 watt meters and they need going through and
> bringing
>
> up to specs and calibrated. Some act as if one or more of the 1N295 diodes 
> might
>
> be bad as well as some resistors have probably changed values over the 30 
> plus
> years they have been around. Heath's carbon resistors  often changed in 
> value
> over the years. I have the following questions:
>
> If you have replaced the 1N295 diodes what number diode did you use to 
> replace
> the 1N295 diodes with? Your recommendations, please?
>
> Do you know if there are any particular resistors and capacitors in the HM 
> 102
> that historically changed value and gave trouble?
>
> Based on your experience and knowledge of the HM 102 watt meter do you 
> have any
> suggestions and tips for restoring the instruments to their original 
> specs? If
> so please share your experience and knowledge.
>
> Your input on restoring these meters will be greatly appreciated. Thanks 
> and 73,
>
> John, K5PGW
> ______________________________________________________________
> Heathkit mailing list
> Home: http://mailman.qth.net/mailman/listinfo/heathkit
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Heathkit at mailman.qth.net
>
> List Administrator: Duane Fischer, W8DBF
> ** For Assistance: dfischer at usol.com **
>
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 10.0.1388 / Virus Database: 1516/3748 - Release Date: 07/06/11
>