[Hallicrafters] Cleaning the inside of HT33A amplifier

[Richard Knoppow]

----- Original Message ----- 
From: <WA1KBQ at aol.com>
To: <k5pgw at yahoo.com>; <hallicrafters at mailman.qth.net>
Sent: Friday, November 11, 2011 3:22 AM
Subject: Re: [Hallicrafters] Cleaning the inside of HT33A 
amplifier


> You might be quite surprised to discover how well that 
> nicotine  has
> preserved everything. It will be quicker in the long run 
> and yield  better results
> if you disassemble the unit, wash everything and blow dry 
> including the
> chassis. I would probably remove the transformers and 
> chokes and  clean them
> separately but you could always try covering them with 
> plastic bags/  rubber
> bands around the bottom and be careful. Richard is right 
> on about the  oven;
> I installed one in my shop and use it a lot, even after 
> blowing parts dry
> they often go into the oven for a few minutes to be sure 
> there are  residual
> traces of moisture left behind (for example: between two 
> flanges  of
> spotwelded sheetmetal). Outside on a table on good hot 
> sunny day  will work also.
>
> Regards, Greg
>
     FWIW, the complete routine we used at -hp- was as 
follows:
     Anything which could be damaged by water was removed. 
This included meters and on some equipment sealed 
transformers and chokes. All sealed compartments, like the 
RF compartment of a 608-C/D were opened up.
     The chassis was washed down with warm water from a 
garden hose. Then washed out with a paint spray gun loaded 
with water and dishwashing detergent and scrubbed where 
necessary with a dishwashing brush. Then it was rinsed with 
warm water from the hose again. Then blown out with 
compressed air to remove as much moisture as possible. Then 
it was baked in the oven at about 130F for at least 48 
hours. I preferred to bake longer but the oven was not 
always available. Some equipment required relubrication 
following washing.
     I don't think this technique is applicable to all 
equipment but certainly worked on the vacuum tube and early 
solid state stuff I was working on at the time.


--
Richard Knoppow
Los Angeles
WB6KBL
dickburk at ix.netcom.com