I'm not sure about the MSR2000, I was in the portable shop already, but,
typically, Motorola uses multi-layer PC boards in most of their radios. Often,
one of those layers is mostly ground plane, a huge heat sink. It's not unusual
to require a higher wattage iron to flow solder on a seemingly small trace on
the surface (the heat is going into a massive piece of foil in one of the inner
layers). The only place, I'm aware of, that Motorola used a higher temperature
solder (silver bearing) is on the ceramic substrates in the transmitters. That
to prevent the higher component temperatures from softening conventional
(especially eutectic) solders. My guess is you're just tangling with a big
ground plane on an inner board layer.
Tom DGN
--- In Repeater-Builder@yahoogroups.com, Eric Grabowski ejgrabow...@... wrote:
A recent thread discussed a problem disassembling a MSR2000 continuous duty
PA. That triggers this query: Does anyone know if Motorola used a higher
temperature solder on the MSR2000 units?
My reason for asking is that this past weekend I had a hard time removing
three leaky electrolytic capacitors from a MSR2000 VHF receiver board. I
ended up using a 45 watt soldering pencil, which I only use for stubborn
jobs, but even it had a very hard time melting the solder on the positive
leads and didn't do anything for the leads soldered to ground. I've never
experienced this before on a PCB. In fact the 45 watt pencil usually works
well on double-sided PCBs with small to moderate groundplanes, although I'll
be the first to admit that it doesn't have enough heat to handle really
massive groundplanes found on some industrial PCBs.
I've replaced components on many a Micor and Mitrek mobile using my 15 and 20
watt soldering pencils without a problem, so this experience came as a
complete surprise. Any thoughts?
73 and aloha, Eric KH6CQ
