|
Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc. |
|
Thread Tools |
21st Apr 2016, 8:03 pm | #1 |
Hexode
Join Date: Jun 2014
Location: Chelmsford, Essex, UK
Posts: 386
|
A77 Optical Sensor
Hi all, a quick request for advice. I'm in the process of refurbishing a nice Revox A77 1/4 Track machine. All is going well and I'm gradually working through changing the capacitors. I have discovered that the end of tape shut off sensor is not working. In a box of spare bits I've bought with the machine there is a replacement optical sensor. Unfortunately it does not have the two wires connected to it, I will have to use the ones off of the one I'm replacing. In the service manual it states not to solder them as the sensor is heat sensitive. The spare I have has obviously been desoldered so it must be possible.
My question is this. Are there any tricks, advice or trade secrets in soldering parts such as these? It must be possible as the existing one on the machine has soldered connections. Mike
__________________
Small Scotch, New Aids and Happy Ears |
21st Apr 2016, 8:11 pm | #2 |
Dekatron
Join Date: Jul 2008
Location: Kington, Herefordshire, UK.
Posts: 3,670
|
Re: A77 Optical Sensor
Usual trick is to put a heat sink between the solder joint and the component - somewhere I have a very neat pair of ali reverse tweezers which work a treat, but a pair of long-nosed pliers would do just as well.
|
21st Apr 2016, 9:43 pm | #3 |
Dekatron
Join Date: May 2008
Location: Derby, UK.
Posts: 7,735
|
Re: A77 Optical Sensor
With good technique and a thermostatic iron fitted with the appropriate sized tip, it's possible to solder most things without overheating them.
When I put a new thermal fuse (obviously temperature-sensitive) in an electric heater, I first cleaned the leads thoroughly, so the solder would take easily; doused the body with freezer spray, gripped the lead with pliers and soldered it as quickly as I dared; and let the whole thing cool down before doing the other lead. It held; but I'll bet it wouldn't have, if I had bought only one replacement thermal fuse and not a pack of five .....
__________________
If I have seen further than others, it is because I was standing on a pile of failed experiments. |
21st Apr 2016, 10:06 pm | #4 |
Hexode
Join Date: Jun 2014
Location: Chelmsford, Essex, UK
Posts: 386
|
Re: A77 Optical Sensor
Hmmm, I like your style but I've only got one optical sensor . . .
__________________
Small Scotch, New Aids and Happy Ears |
22nd Apr 2016, 6:38 am | #6 |
Dekatron
Join Date: Jul 2009
Location: Sleaford, Lincs. UK.
Posts: 7,658
|
Re: A77 Optical Sensor
A croc clip, bulldog clip etc works as a heatsink and using a hot iron and flux helps too. It's about dwell time Mike, IE how long your iron is on the component. With a good hot iron, and a bit of preparation and forethought it's pretty straight forward, same as soldering batteries. See this video ..... at around 24:00 https://www.youtube.com/watch?v=HqsXe3IKTCo for how to solder batteries, perhaps you could practice on a few dead ones to get your technique down first?
Andy.
__________________
Curiosity hasn't killed this cat...so far. |