Adventures with BPC TV set

[wa2ise]

Have an old "Aiwa" TV-VCR combo where the VCR part failed some years ago. The TV part worked as a color monitor and I decided to install a DTV converter box in it, where the VCR part once resided. Seems straight forward enough but just before or after I pull the back off, something decided to fail in the monitor. The off line switching power supply was squealing, and the control line (from the VCR part) no longer had any effect, nor the 5V standby supply was there. Seemed the supply was acting as it had a short on an output. Okay, check rectifier diodes. In circuit they all seemed shorted, so unsolder one end, all but one test okay. Bad one was truely shorted. Power supply became happy with it out. Okay, need a replacement. Need to be careful, as an ordinary 1N4007 diode is fine for 60Hz work, but not for switching power supplies. Well, I pulled a diode from a junked computer CRT monitor, one that did the 150VDC supply like the one I needed to replace. The TV works now, and seems quite happy with the new diode.

Now that I got that out of the way, time to integrate the DTV converter box. The TV has (as mentioned above) a control line that wants about 5VDC applied to turn the TV on. Else it's in sleep mode. Well, the "Digitalstream" DTV box I'm going to use has switched 5VDC that feeds its tuner module. Easy enough to tap that and feed it to the TV control line. Now, the DTV remote also turns the TV on and off with the box. And this converter box can vary the volume of the audio jacks via the remote control, so all I need is an audio amp to drive the TV set's speakers (used to be part of the junked VCR module that is long gone. The TV supply supplies controlled 12VDC which used to power the VCR, but now powers an audio amp.

Tomorrow I'll package this up. Then I'll have a small DTV CRT set.