How To Un-Mod Heathkit DX-100 Ham Transmitter Repair Grid Drive

This transmitter came to the shop with no Grid drive. I noticed a modification on the front panel consisting of a 1/4" input jack plus Pot. I could not find anything on the web describing this mod. So, I inquired on the DX-60 net. Everyone agreed, it may be added FSK keying. W8TOW recommended that I remove it as it can affect the VFO operation. So after evaluating the circuit, I found that it was integrated into the vfo compartment. Hours later, I un-modified the transmitter. Lucky for me, the Grid VFO and drive returned to normal operation. Taking the VFO apart was not a pleasant task. Remember if you modify a piece of equipment, someday another will have to undo it. So, make sure to document and insert into the manual. In this case, I had the Heath construction manual to verify original wiring. Thanks to Heathkit for clear building instructions. More repair required on this transmitter. Been out of commission for many years. I enjoy this type repair, just lacking free time. So bear with me my friends.

[@rciancia]

Terry, this is what sets you apart from the other guys I watch. You have a solid understanding of how to trace these things and how it should be... that is an art you do not learn overnight.. lots of sweat, shocks and determination. Well done ! Ron

[@d-labelectronics]

Thank you Ron. Appreciate you sticking by my side. TD

[@timsaarinen3074]

Now you can't talk to aliens on it.

[@TheRadioShop]

Top notch as always Terry. Thanks for sharing

[@langhilau]

Great video Terry as always.

[@robertcalkjr.8325]

Thanks Terry!

[@langhilau]

Never mind, I see you did one.

[@RobertKohut]

Nice!!

[@irondogindustriesllc9025]

Just removed an extremely similar mod to my DX-100. I am back on the air with about 80 watts, albeit with a bit more chirp that others

[@langhilau]

Hi Terry is there any chance you could make a PTT module for a Johnson Challenger?

[@willrobbinson1]

I agree PLEASE DOCUMENT mods & put it with manual its seems silly but a few years later u ask yourself what the heck is that wire thing (mod)done years ago ?ect. its so easy to forget & it saves a lot of time down the track . I did it resonantly with home brew 813 amp almost finished on shelf few years scratching head whats that wire for!! my notes I made showed the reason. good work good lov watching old gear live again ect

[@lwilton]

Problem is, the guy that had it as the pride of his ham shack gets old and dies, and the kids that never knew what was in that room sell it all off, and throw all the papers in the filing cabinet away. So much for carefully documenting it in his manual.

[@jimw7ry]

@@lwilton Agreed I Wilton!!!! As if the original manual is always kept with the radio! 😂

[@dri50]

Makes me think twice about bidding on that DX-100B that has wires hanging out the bottom !

[@d-labelectronics]

Yep, I see that one on ebay, steer clear