I am Also working on a Whamo-10, downloaded your 4 attachments, Thanks ! Do you have any more info/schematics, on this scanner ? Mine worked a few time, but after I tapped on the VCO board, it is Not generating a signal, for the first ,Oscillator .High folks... My first post here. I've been a looker for a while, now I need some help. If I'm in the wrong section please let me know.
I'm working on an old Regency Whamo 10 scanner... If anyone remembers these, they were one of the first "Programmable" scanners. These use "Programming Combs" to set the frequency on each channel. You break the teeth off the comb to set frequency. So it turns out that with the unit programmed to 154.415 Mhz, it is actually receiving at 156.415. Looking at the programming sheet we see the following:
O = TOOTH PRESENT X = TOOTH REMOVED
Frequency ___ ___
1 154.4150 XOXOXXOOOXOXOOOOXOOO
2 156.4150 XOXOXOOOOXOXOOOOXOOO
So it appears that the issue is with the 6th tooth in on the unit... I have traced this 6th position back to what is called the "Divide by N" board in the scanner itself and down to an IC on that board known as IC512. Looking at the service manual (which is not complete) the voltages are lower then what they are supposed to be on the pin that this line runs to on the IC. This is where I am currently stuck. I do some component level stuff, but I'm not sure where to look next on this issue.
I have attached the schematic for the unit and the pages out of the manual relating to the Divide By N board. I'm hoping maybe someone can shed some light for me.
I have IDed what each board does, my RF-IF-Audio board is good, as is the decoding of the 20 tooth combes . I have also IDed each IC on the 400 and 500 board . I have picture and paper work avaliable from my research . JIM
Moderator edit: New thread started from old one (this link below).