[50mhz] Re: 50mhz Lafayette HA460

[manualman@juno.com]

Bad audio, check and replace the two capacitors (.02) going to the grids
of the audio/modulator tubes. They're always a problem. Also check the
cathode resistor (100 ohm 2 watt); Check and replace both capacitors
(.01) across the center tapped primary of the modulation  transformer.
Also check the screen resistor (8.2K 2 watt) for the 2E26. Some folks
lower this value to squeeze a hair more power out of the tube. Also,
check all the resistors in the power supply section. The transceiver
always ran hot; great footwarmer. Because of the heat generated under the
chassis, over time many of the higher current carrying resistors may have
changed value. Be aware that although the schematics say 6GW8 for the
audio/modulator tubes, there were some early 410's and 460's
manufacturered with a different set of tubes. Some pin differences and
there were no schematics printed with these earlier tube numbers. Another
one of Lafayette's great undocumented design changes.

Pete, WA2CWA

On Sun, 13 Apr 2003 19:17:43 -0500 Chris Boone <cboone@earthlink.net>
writes:
> 50mhz reflector
> 
> Found a HA460 at a local resell shop....brought it home with intent
> on putting it up for sale (I have no use for it but didnt want it 
> see
> it go to waste where it was)...checked it out on my CE50A...
> TX was doing about 12 watts out, seemed to modulate ok..but the
> audio sounded pretty BAD on the svc mon....rcv was ok....while 
> checking
> it I started to smell something...saw a whiff of smoke out of the 
> center
> of the unit...(pretty close to the 6CW4 rcv amp..)....Unit HAD been
> modified with a fan on the top (evidently this was an ongoing 
> problem).
> I suspect a resistor opened...though unit is still functioning 
> now..
> but I have not taken the cover off yet...anyone ever have this 
> problem
> with a HA460? Overall the radio is in pretty good shape (except for 
> the
> hole they cut for the fan in the center of the cabinet top!) Found 
> the
> schematic and plan to dive in later this week (BTW I might add it 
> has
> the mobile mount and std mic with it...yes, it will be offered for 
> sale
> or auction later AFTER I fix it)..
> 
> Tnx
> Chris
> WB5ITT

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