Well, the TR-7 from hell is now a fully operational TR-7 from hell! In preparation for some signal tracing, I decided to extend the DR-7 board using the extenders I have. To do this, you have to unmount the two voltage regulators mounted to the chassis, and jumper the connector farthest to the right. (I didn't bother connecting the up/down band buttons.) Lo and behold, the display worked!
Some further investigation revealed that the chassis has warped over the years, so the two 3-prong connectors on the VCO board were no longer in a horizontal line. So I was determined to make sure the board was fully seated on all the connectors. To do this, I had to drop the front panel. Not a major chore, just one knob to remove (the band knob) and 6 side screws. With that now out of the way, it was an easy job to determine if all the pins were where they belonged. The only snag was that the front panel, when canted downwards, angles the PTO can upwards. So you have to hold the front panel perpendicular and steady with slight downward pressure to fully seat the board. Once all the pins were visually confirmed to be seated, I remounted the front panel, reattached the regulators and all the connectors, and fired the rig up. Everything now seems to work! It turns out the original DR-7 board was indeed defective as well (possibly because it had been seated incorrectly). And a visual conformation from topside indicates the chassis is, indeed, warped: The screw hole is misaligned with the mounting hole in the board. So, for archival purposes in case anyone else decides to search for this problem: If the display if fixed on "51950", one possible cause is that one or more DR-7 pins, possibly the VCO pins, are not correctly seated. The best solution is to drop the front panel and confirm visually that the pins are fully seated. Now it's time to get on the air! --Brian/WA3ITE _______________________________________________ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
