[Hammarlund] HQ-170A mods?

[Peter A Markavage]

The reactor or filter choke value for this receiver is 8 henries.
Anything close would also work. In the 170A VHF the 3K, 10 watt resistor
you quoted, should be 2K, 10 watt. The 170A VHF uses a smaller value than
the 170A. The OB2 is correct. It should provide 105 volts regulated on
pins 1 and 5 of the OB2. Check and trace the two wires coming out of the
reactor to see where they are going. One side should go to the cathodes
of both diodes and the other side should connect to the lead of the 2K,
10 watt resistor not connected to the OB2. Filters caps are hung on both
sides of the reactor leads.

Pete, WA2CWA

On Fri, 2 Jan 2004 18:49:17 -0500 "Craig Roberts" <crgrbrts@verizon.net>
writes:
> Thanks for the info, Chuck -- 
> 
> Yup, I know the OA2 and OB2 tubes are different. The OB2 takes the 
> lower
> voltage -- which is why it's glowing unnaturally bright orange when 
> run off
> the modified higher voltage circuitry that accommodates the OA2  
> I've
> reinstalled the OA2 but would, as suggested, like to return the rig 
> to
> stock.  However, I'm not sure I can get the parts to do that.
> 
> For instance, that mysterious gray "thing" in the power supply 
> circuit is
> apparently the "reactor".  What the heck is that???  I guess it's a 
> choke -- 
> but I don't know the value.  I'm thinking the "reactor" might have
> "overreacted" and blown up (which would explain its overheated 
> appearance)
> and a previous owner modified the circuitry around it employing two 
> extra
> diodes and the OA2 because he couldn't figure out what it was, 
> either -- or
> a suitable substitute wasn't available.
> 
> Anyone know anything about this device?
> 
> Thanks again,
> 
> Craig
> W3CRR
> 
> _______________________________________________
> List Administrator: Duane Fischer W8DBF
> ** For Assistance: dfischer@usol.com **
> ----
> http://mailman.qth.net/mailman/listinfo/hammarlund
> 
>