[Heath] SB104 question

[Mike Bryce]

Heathkit, like so many others at the time, used a bit of smoke and mirrors in the design of the display of the 104

In a nut shell, the display is nothing more than a frequency counter.

they use presets to 'preset' the display

pull or lift out all the boards except for the 'a' board and the 'b' board

put the band switch in the 3.5 mhz position

release the usb, lsb and cw switches. (all out)



power up the rig

you should see 6600.0

press usb and 6603.6

press lsb and 6606.4

and cw and 6604.3

if you don't then there's a counter problem. Start by verifying that the counter has a good solid +5 volts to it.

then power down, pull the counter board and gently remove the IC one at a time, then reset it into it's socket. Do just one IC at a time so you don't mess up where they went.

It's possible that you have a fubar driver chip on the display board, But I've found that they usually fail they cause missing segments or dual segments to light.

just sub out one of the chips on the display and see what happens


Let me know...

Mike, WB8VGE





On Oct 31, 2011, at 9:54 PM, Morris wrote:

> I've read that the 11 volt regulation is often the culprit for display problems.   I haven't experienced it on mine yet.   See what it reads, especially when the failure occurs.
>  
> GL,
> Morris
> 
> 
> -----Original Message-----
> From: heath-bounces at puck.nether.net [mailto:heath-bounces at puck.nether.net] On Behalf Of KP2N
> Sent: Monday, October 31, 2011 9:05 AM
> To: heath at puck.nether.net
> Subject: [Heath] SB104 question
> 
> Our club was donated a SB-104, SB-644A Remote VFO, and speaker/power supply combo.
> After much cleaning inside the radio works.
>  
> The newest problem is the frequency display.  The gas discharge tubes seem to be ok.
> When in the 20 meter switch position the display reads 15255 instead of 14255.  The rig is
> receiving on 14255 so there is a display problem.  15 meters is reading correctly but 10 meters
> is reading 1 MHz high 29400 instead of 28450. 80 and 40 meters seem to read correctly.
>  
> I am sure this question has been asked years ago but we just received this radio and it has
> a lot of history behind it.  Would like to get it operating correctly.
>  
> If you can indicate where to start to look it would be much appreciated.
>  
> 73  Ron  KP2N
> St. Pete, FL
>  
> _______________________________________________
> Heath mailing list
> Heath at puck.nether.net
> https://puck.nether.net/mailman/listinfo/heath

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