[Hallicrafters] HX-500 serial numbers

[manualman at juno.com]

On Page 10 of HX-500 Service Bulletin, 5001-1, they made reference "In
all HX-500's produced, with serial numbers under 1000...". So somewhere
on the chassis they must have tagged, stenciled, rubber stamped, etc. the
serial number. But after 50 years, tags fall off, ink gets wiped away,
etc. 

It's also worthy to note, that besides this 12 page service bulletin,
there was also Instructions, K52778-1, for a "improved power transformer
replacement" and replacing the 12AX4GTB's to a 5R4GYB and the use of
solid-state devices in the bias rectifier circuit. The modified power
supply circuit is included with this information. So there are probably
HX-500's out there that have been modified to use this new transformer
and a single 5R4 instead of a pair of 12AX4's. 

As far as I can tell, the HX-500 schematic (the one that came with the
manual) was never updated to include any of the changes that were
designated in Service Bulletin, 5001-1, nor was it updated with the
change from 12AX4's to a single 5R4 and the changes to the bias rectifier
circuit.

Pete, wa2cwa
www.manualman.com



On Wed, 17 Jun 2015 13:08:51 -0500 Brian Harris via Hallicrafters
<hallicrafters at mailman.qth.net> writes:
> I have an HX-500 with no obvious serial number however it does have 
> an X13 stamped in the rear apron.  Might that be the serial number?  
> I am interested to know what your 500 might have.   Thank you, Brian 
> wa5uek
>