Motorola Sapphire XVIII tuner control repair

[vw73bug]

Hello everyone,

I'm a first time poster but long time lurker whose found these forums very helpful since I inherited a 73 Bug a few years ago. So, first, thank you!

My question: I've got a Sapphire XVIII radio in really good shape, except that the tuner knob no longer works, but simply spins freely. I pulled the radio and opened it up to find the problem. Apparently, the shaft turned by the tuning knob features a universal joint, the forks of which are fixed to the ends of the shaft with what look like hollow tube rivets. One of these rivets is worn/broken, so now the knob and u-joint spin independently of the rest of the tuning mechanism, thus the problem.

Any advice/ideas on how this rivet might be fixed? I was wondering if a spot or two of solder might be strong enough to make the shaft solid again. The dial seems to put up a lot of resistance, so its probably full of gunk that needs to be cleaned out (the tuning mechanism inside the radio operates manually easily and smoothly, however).

Thanks!

[cletus_zuber]

Search radio repair in the classifieds. There's a couple guys here can help.
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1972 1302
HPMX 40's & 019

[ghia4mea]

I don't have the same radio as you, I have the Sapphire XIV but it has the same tuning drive setup as your radio. I checked with a magnet and the tuning shaft that the knob goes on is solderable. The tough part is cleaning the parts well enough to do a good solder job.
The shaft that has the gear that engages the white plastic gear is pot metal or aluminum and cannot be soldered. If that side has the issue, I would clean it well, apply crazy glue GEL, and after that has set properly, I would add a bit of JB weld Clay, not the liquid stuff.
I can't think of any other good/proper way to repair this problem. I have repaired several of these AM and AM/FM radios, and these type of mechanical problems are not unusual in gunked up radio drives. The clutch often gives slipping issues too, but can be adjusted.
Good Luck

[vw73bug]

[Cusser]

Several suppliers make an epoxy stick product, sold at retail.
_________________
1970 VW (owned since 1972) and 1971 VW Convertible (owned since 1976), second owner of each. The '71 now has the 1835 engine, swapped from the '70. Second owner of each. 1988 Mazda B2200 truck, 1998 Frontier, 2014 Yukon, 2004 Frontier King Cab. All manual transmission except for the Yukon. http://www.thesamba.com/vw/forum/album_page.php?pic_id=335294 http://www.thesamba.com/vw/forum/album_page.php?pic_id=335297

[ghia4mea]

Yes that is the correct stuff, epoxy putty stick. I keep it on hand as it is very handy stuff. Can be shaped and placed most anywhere. Just try and clean the surfaces well for good adhesion.
Good luck.

[vw73bug]

[ghia4mea]

Ok that sounds good. You might want to make a fillet of JB weld on the back side of the fork and extent it around the shaft, there seems to be plenty of room. This will distribute the stress onto both sides of the fork.
Let me know how you make out.

[vw73bug]

[vw73bug]

Success! Took a few tries, but some needle-nose pliering, jeweler tooling, and a bit of shameful (but soothing) swearing got the freshly cured section of the tuning shaft back into place. The epoxy is working so well, it was making it difficult to spread the fork wide enough to get the u-joint snapped back together (ghia4mea, I took your advice and added additional epoxy around the base of the fork; there was plenty of room, and the joint now seems very strong). The tuner now operates cleanly and smoothly.

If this repair can withstand the abuse I just gave it, this radio ought to last for another 40 years.

Thanks for the help and advice ghia4mea, and everyone!

Trying to upload a video of the working radio to the gallery, but apparently it doesn't take video Here's a pic instead:

[ghia4mea]

Beautiful job! I bet it lasts a long time. Cleaning the rest of the moving parts and a tiny bit of lube will smooth things out and make tuning easier. Be careful not to get any lube or oil on the clutch surface or its mating surface.
Happy Trails!

[vw73bug]

Thanks again.

[jim_hoyland]

Terrific post ! The pictures are really good; my tuner knob became inoperative and I opened the case thinking I had the same problem. It turns out that the green plastic toothed gear ( shown in the pics) broke. I have two pieces that are loose and the hub is still on the shaft.
I think the pieces could be glued back together, but I can't figure out how to get the hub off the axle.

My initial question: Is this part replaceable, or even available ? Has anyone done this repair ?

Here's a couple of pics of my parts: The radio is a Sapphire XXIII

[Teafortwo]

A wild suggestion for a high tech, low cost solution.

Recently the small gear in my speedo split, a common fault in VW's. My neighbour has just bought a 3D Printer and was intrigued by my dilemma. Also he was desperate to try out his new toy. He took my gear and a couple of hours later came back with a very passable copy. I've not yet had a chance to try it, so no guarantees. All he did was measure the diameter and shaft size, count the teeth. He has a generic program so was able to draw up the gear. The printer did the rest.

Your gear wheel is quite fine, but it may be possible to get one printed. Does anyone on The Samba have a 3D printer and willing to give it a go?

[jim_hoyland]

[Teafortwo]

My low tech suggestion would be to use epoxy glue, I favour Areldite. It is slow to set but can be speeded up with a hair drier. Once set you might need to take a very fine file to remove any residue glue from between the gear teeth, where the joint is. Worth a try because the wheel is basically scrap as it is and when the mechanism is freed up and oiled it should work OK, it is not performing a high precision task.
For the wheel to fail so catastrophically, it suggests a jammed mechanism suggesting that any Sapphire should be opened and checked prior to spinning the control.
If we consider the previous failure of the peened rivet and your shattered wheel this may be a common failing, which could be avoided by lubrication.

Good luck!

[jim_hoyland]

For those looking to buy a used Sapphire, or any other vintage unit; I would recommend opening it up and oil the tuners moving parts and look for previous repairs.

I ended up sending my unit to the Radio Doc in Florida.