> If you're any good at electronics and soldering and your scope is
> out of warranty, you might just swap the serial port chips. If I
> remember right they are the common 1488 and 1489 RS-232 line driver
> chips available at Radio Shack.

If these chips are mounted in sockets, swapping them is a piece of cake - just be sure to orient the new chips the same way, and be sure that all pins go into their holes in the socket.

If the chips are soldered into the PC board, here's a procedure to remove them, while minimizing the chance for damaging the PCB.

1) Gather tools: 30-50 watt soldering iron with chisel or round tip; rosin-core electronics solder; desoldering braid (copper braid impregnated with flux); small needlenose pliers; small wire cutters.

1a) If your soldering iron doesn't have a grounded tip, ground it yourself temporarily. Strip one end of a 6-foot length of wire and connect it to the cover plate screw on a power receptacle, then strip about 6" of insulation and wrap the bare around the soldering iron shank. Remove this temporary ground wire when done working on the Meade electronics.

2) On the component side of the PCB, use the wire cutters to sever each of the 14 pins on the chip. That's right - cut the legs off the bugger! When you're done the chip will be free and there will be 14 little spears sticking out of the PCB.

3) Melt the solder on each pin, and pull it out of the PCB with the needlenose pliers.

4) When all pins are removed, place the desoldering braid over a hole and heat the braid with the soldering iron. When it gets hot, it should wick the solder out of the hole. Do this as quickly as possible to avoid delaminating the copper traces on the PCB.

5) Solder in a SOCKET for the new chip. You've just done 90% of the work of replacing a chip, so you might as well install the new one in a socket so you don't have to repeat the procedure.

6) Insert the new chip in the new socket, and you're done.

Hope this helps.

Mike

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