800B Replacing a Broken Contact of Preset Tuning Assembly

[Joseph W Strickland]

Reference Figure 24 of Page 53 in the 800B Service Manual

I received two replacement short contacts from Norman Brathwaite to use in repairing the broken one on the unit I have. Let me tell you - this is a major pain to put back together. The reason is that when doing so you have to hold the Knurled Thumbscrew (15) on the backside into the other pieces, get them all in the correct stack order with the compression spring (24) in place, then put the final Hex-washer (25) that has the slot in its top in place, compress it enough to see the tiny hole for the retaining pin (37) to go through. The tendency is for you to slip at the last instant while trying to insert the pin. When that happens you have Jesus parts flying all over creation. Then you spend the next amount of time (up to 30 minutes or so) looking for the tiny pin (or other parts) which was made originally from music wire (read metal guitar string). I lost count of how many times I lost it and had to look for it. Try finding such a tiny part if it falls into thick pile carpet!!!

My solution: I finally realized that trying to insert that tiny pin that is so short was a nearly impossible task. I decided to try using one of my wife's straight pins from her sewing kit (not the actual sewing needle). These usually come with a head that can be grasped with fingers while you get the point started in the tiny hole through the Knurled Thumbscrew (15) shaft. Once you get it started you can remove the awl or whatever you use to initially get the top slotted hex-washer (25) slot lined up with the Knurled Thumbscrew shaft opening. After you have the pin coming out the other side, just take wire cutters and snip off the pin head and then the excess on the opposite side.

I have two kinds of awls to use. One is straight and comes to a pretty fine point. The other one has its tip at a 90 degree angle to the shaft. I used the 90 degree awl so that I could put its handle in my left hand and press down on the slot in the slotted hex-head washer (15) until I could get its point inside the Knurled Thumbscrew shaft hole all the while keeping spring (24) compressed. Keep the awl point in the shaft hole (this action holds the whole assembly together) while you grab the straight pin and insert it in the Knurled Thumbscrew shaft hole from the other side. Once you get the straight pin into the hole, keep pushing and allow the awl to be pushed from the other end of the hole and push the pin in until the point comes out somewhat beyond the slotted hex-head washer (25).

The nemesis of the whole situation is the compression spring. If it were not for the necessity of that one part it would be far easier to reassemble.

Although I lost the OEM pin somewhere in my study, I found a solution which worked far better than the OEM pin. Some straight pins that come with purchased clothing have a plastic knob on the end to make them easier for customers to pull them out when taking the clothing item off of the store packaging. We always save those for future use. Those are even easier to work with. Just make sure the one you choose is close to the original pin size so that it can stand the stresses caused by the compression spring. Inserting the original pin using pliers proved to be very difficult.

Here is the stack-up drawing I made with reference numbers to the diagram shown on page 53, figure 24 of the 800B Service Manual.

[Kent King]

Joe, that diagram is awesome. I will gladly add that to the Archive materials for the 800B. Very helpful!

Kent

[Joseph W Strickland]

Kent;

Thanks for the kind words. I want to be helpful to others that may tread the same path in restoration of their 800B. Thanks also for your own efforts in maintaining this site and compiling data on all Scott models.

Joe