B & W 370 SSB adapter

[WA2TTP Steve]

I was recently given a bunch of gear that had belonged to my dentist's father who passed away a year ago. A nice surprise to say the least.

Included was a TMC GPR 90 receiver that I would like to team up with the B & W 370. Both are in excellent shape for the most part except for two frozen controls on the 370.

My questions are these. Has anyone used the B & W 370 and is it worth fixing it's controls.

Any suggestions on freeing up the controls? I put a little penatrating oil on the shafts and let it soak overnight but they won't budge. There is no rust or corrosion on the unit at all so its a mystrey why they froze up in the first place other than age.

One is the volume control which I can replace but the other is the sideband selector/AM switch which special.

My feeling was to unmount the switch and remove the wafers and the retaining clip on the shaft and gently drive the shaft out and clean up whatever is causing the problem.

73,
Steve
WA2TTP

[KA0HCP]

I would give the penetrating oil several days to work.

Do not hose down any phenolic wafer switches with cleaning/lube compounds like De-oxit.  The phenolic will absorb it and swell making it difficult to turn the switch.  It can takes many months for it to evaporate and shrink.

[WA2TTP Steve]

I gave it another shot of P oil today and I'll give it more time to do its thing.

[W3GMS]

I was recently given a bunch of gear that had belonged to my dentist's father who passed away a year ago. A nice surprise to say the least.

Included was a TMC GPR 90 receiver that I would like to team up with the B & W 370. Both are in excellent shape for the most part except for two frozen controls on the 370.

My questions are these. Has anyone used the B & W 370 and is it worth fixing it's controls.

Any suggestions on freeing up the controls? I put a little penatrating oil on the shafts and let it soak overnight but they won't budge. There is no rust or corrosion on the unit at all so its a mystrey why they froze up in the first place other than age.

One is the volume control which I can replace but the other is the sideband selector/AM switch which special.

My feeling was to unmount the switch and remove the wafers and the retaining clip on the shaft and gently drive the shaft out and clean up whatever is causing the problem.

73,
Steve
WA2TTP

Steve,

Don't overlook where the switch shaft goes through the bushing.  A little WD-40 is good to use.  If you look at the wafers in the switch structure they generally do not freeze and if so are easily undone with a little lubricating cleaner.  It does not take much but don't overlook a frozen shaft. 

I have the B&W 370 that Jack Williamson gave me.  Its a very good unit and well worth restoring. 

Have fun with your new acquisitions!

Joe, W3GMS

[WA2TTP Steve]

Joe,

The shafts are frozen in the bushings for sure. I ordered a new pot and will be taking the switch apart to free it up if I can. If not I think I can mix and match parts from other switches in my junkbox.

Steve

[K7NCR]

I had the same problem with shaft bushings on my Indian twins. I work in automotive, so I tried GM heat valve lube. It is stinky, burns open cuts on your hands, and works GREAT! But be careful, it is powerful stuff! A "little dab 'll do ya'".
New part number is 88862628.

[w1vtp]

The last post is probably a good idea.  I'll have to get some of that.  I had a Dynaco PAT 5 that had a frozen shaft and nothing would fix it except the application of heat.  I used one of those heat shrink guns with plenty of protection against collateral heat damage.  It did the trick.

After freeing up the shaft I then applied some penetrant and the shaft still works.  Problem is a combination of corrosion and the grease turning to a pasty wax so sometimes you need to do the heat thing plus the penetrant thing

Al

[WQ9E]

I have found that using a soldering iron to apply a bit of heat to the shaft and then a few drops of synthetic oil as it cools will draw the oil in.  A couple of applications usually does the trick.

Be careful of any heavy duty chemicals around pots because it can dissolve the bond between the carbon and its mounting surface.

[WA2TTP Steve]

Update.

I tried the heat trick by using a small butane lighter on the shafts and then applying P oil to the shaft/bushing. After this I was able to move both controls with pliers but there both still pretty stiff. I put some synthetic oil on them for an overnight soak.

Thanks for everyones input.

Steve

[WA2TTP Steve]

Update.

I finally got back to the B & W 370 with it's frozen controls. I replaced the volume control with a new one. The function switch had to be disassembled in place, there was enough slack in the wiring to do this, and the shaft and bushing removed. I placed the shaft in a bench vise and used large pliers to remove the bushing. The shaft was a little burred but with some polishing it was fine. A little lube and re-assembly and it works smoothly.

The 370 worked after a slow ramp up of line voltage. I did a little touch up on the alignment and it's working well with the TMC GPR90 receiver. SSB and AM sound good. Very selective.

Thanks for every ones input.

73,
Steve