[Heathkit] SB 102 - 7W Audio board resistors

[Greg Mijal]

Hello Carlos:

You have a very good radio there.  I run an SB 101 nearly every day and 
enjoy it very much.  Concerning the resistor problem you mentioned, here's 
what I would do:
Remove both power resistors and measure the resistances.  Also, tug on the 
leads and make sure they are still anchored inside the blocks.  If the 
resistors pass, then re-install them and do the resistance checks as 
described in the 102 manual.
If they pass this test then the next thing to do, based on the "5 minutes 
after turn on  the resistors fry" comment is to remove all the tubes and 
turn the radio on for 5 minutes.  No frying means you have a tube problem. 
Frying means a bad component or wire.  The best way to find the fault is to 
trace out where the regulated line goes to in the circuit, then disconnect 
all branches then re-attach one branch at a time until the fault re-appears.
The Heathkit SB and HW transceivers seem to need tweaking from time to time 
based on the type of construction and parts used so while you are working on 
the rig, it's a good idea to clean up relays and re-tighten board to frame 
screws.  Also, the phono jacks at the rear could use a squeeze with a pair 
of pliars to the center pin to eliminate any intermittants.
Good luck and have fun.
73's
Greg
WA7LYO
Kinston NC
----- Original Message ----- 
From: "Carlos A Archilla" <caab at libertypr.net>
To: <heathkit at mailman.qth.net>
Sent: Monday, April 26, 2010 9:57 PM
Subject: [Heathkit] SB 102 - 7W Audio board resistors


> Hello to the list:
> I was lucky to find resitor (Part No. 3-15-7) frying about 5 minutes after 
> I turned the old SB 102 on. It is clear that the 1K ohm 7W resistor must 
> be replaced and maybe the 2.5K ohm 7W (3-16-7) resistor next to it too. 
> But before I do.....is there anything I should check other than the Power 
> Supply 300V B+ line?  Any known source for these.  Any help would be 
> appreciated.
>
> Carlos KP4GL
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