JRC repair tips and tricks

[N8YX]

Tip 3 - There's a bug in the machine

When I began tracing suspected BFO leakage problem with my RAY-152, I threw the symptom out on various mailing lists to see if anyone else observed the condition.

Surprise...they ALL do it. With the display backlight turned on. It's not BFO leakage. It's an audio tone from the DC-DC converter circuit used in the backlight, for generating voltage required for the EL panels. Somehow this is getting coupled into the Mic Amp circuit.

I tried all the usual fixes (electrolytic cap replacement, bypassing, filtering) and didn't make much headway. Someone from the PNW had a friend who knew how to fix this problem but unfortunately the gent went SK before passing on the knowledge. I may try contacting Raymarine for any Service Bulletins they may be aware of, -but for now, turning the backlight off addresses it.

[N8YX]

Tip 4 - Boards Bounce

Got a fully optioned NRD-525 from overseas. While the rig was packed fairly well, a month and a half of being jostled around resulted in almost every board in the unit walking off its connector set.

FYI, the NRD-525/535, JST-135, JSB-176 (and re-branded RAY-152) plus a number of other marine receivers used motherboard/card-cage construction techniques. There are guide tracks for each board, and while these usually are a snug fit they'll sometimes let the various circuit boards slip out of their edge connectors. This resulted in an inoperative receiver - no audio, erratic S-meter/AGC operation, etc.

Re-seating all the boards fixed it. I'll usually look at the various loop lock lights on the Ref DDS and Loop 1 boards as a start point when troubleshooting one of these rigs, but this particular problem was evident at first glance.