Minolta SRT102 Wiring Repair

I recently won an auction on eBay for an SRT 102. Cosmetically, the camera looks practically brand new. Functionally, though...

 

I can't seem to get the meter needle to budge, either when the meter is on, or when I've turned on the battery check. I've tried new batteries and I've tried giving the sides and bottom of the camera a "whack" to see if it was just stuck on something.

 

Last night, I took the bottom plate off the camera to see if I could find any issues with the battery connection. In the area of the battery check/meter switch, there is some sloppy solder work, and I'm pretty sure that the blue wire has been cut shorter and re-routed.

 

I've attached a picture from my camera that shows the state of the wiring.

 

And here's a link to what I think it's supposed to look like:

Minolta SRT 303 Bottom Flat Spring

 

I didn't pay much for the camera, so I'm willing to try to re-solder these wires myself. Any advice for the effort?

 

Also, I have seen some threads where people recommend "checking the continuity" to see if there is a wiring problem somewhere. I'm not sure I understand what points I should use to check the continuity, though.

 

Thanks in advance!

 

Mark

 

As o the soldering, I've had varying luck with this and the only thing I can recommend is that you find the tiniest soldering iron tip you can, and the smallest gauge solder, and wear magnifying glasses even if you're not already far sighted.

 

As for the blue wire, you are right, and given that this has been fudged, I suspect you're headed in the right direction, but have no wisdom to impart on testing things.

 

Here, though, is what the innards of an SRT-102 are supposed to look like (well, maybe not that blurry, but I was in a hurry):

 

I think Matthew'S comments are right on. Assuming Matthew'S photo is the factory untouched. AS mentioned someone has done something here with the routing of the blue cable. IT seems to be in the right place. The continuity check would be to follow from the other end of this blue cable to here with a meter. What is the blue wire supposed to be doing? Guessing a fallible person like me re-soldered that blue cable for some reason..as Matthew said you're on the right track. You might just heat up the ie re seat the end joint..

Thanks, Matthew and Chuck!

 

I might try "extending" the blue wire with another piece and some heat-shrink tubing. I found a wiring diagram in the SRT101 service manual this morning, so I think I have a good idea of where everything goes.

 

That looks useful. I would just add that I note in your picture above that the switch contacts look a little skewed, and I'd check to make sure it's all lined up right mechanically. It looks as if the meter switch is simply a cam that pushes the contacts together, so it looks pretty important to have it all straight.

 

I've never gotten deeper on mine, because it works (keep fingers crossed).

Yes that blue wire needs to be re-done, back to original. The 303 link shows it's layout very well

 

A continuity check is simply checking for "open circuit", a broken or pinched wire, or a corroded joint whether soldered or clamped or under spring tension

 

Re: Light meter. I had the same problem with a Petri FT, it was almost new old stock, but the light meter was way off, it had a broken wire on one of the cds cells. The wire was as thin as a human hair and not repairable so I swapped the cells and their circuitry from another Petri and now I get beautiful exposures. Before that, I was using a handheld meter

 

On your camera, the next step, and it's only a suggestion, is to move the variable resister arms on the reostats around a bit to check if they're making good contact

 

Moving the arms is a delicate operation. Strong arm tactics might result in permanent damage, great care is required

 

Mark the original positions of the arms, then move them around but bring them back to the marks when you're done

 

This procedure will "clean" the connection between the arms and the reostats' resisters

 

 

Arrows show the arms