Folks
I believe that there is a lot of similarity between these test sets, I have had an MT8802A for about four years now with the spectrum analyser (option 07).
Over the past three years, although the analogue receiver tester has been working perfectly, the analogue transmitter tester and spectrum analyser have been misbehaving intermittently to the extent where I'd stopped using them. Most notably the tx tester worked increasingly intermittently or was terribly deaf, and the spectrum analyser was unstable or otherwise significantly off frequency, and it did not measure levels accurately.
Although the symptoms weren't specifically mentioned here
http://www.kolumbus.fi/oh5iy/HW/MT8802A.html I decided to bite the bullet and do an electrolytic transplant over the past day and a half.
The results have been superb, all of those intermittent problems appear to have gone.
I wouldn't recommend doing it unless you have a lot of patience and you can accept having the unit out of action for a couple of days. There are tons of screws to keep track of, and about twenty boards to get through. The power supply and A10 converter seemed to fix most of my problems, and I did those first anyway, but I thought as I'd already started I might as well do the lot.
Removing some of the caps wasn't always easy. I used a Weller DSX80 on a WMD-3: they've been in a box for about four or five years as I only really do SMD on boards these days for projects, it's very rare that I need a through hole on a board. While it worked, much of the time I found that touching up the exposed cap pin stubs on the underside of the board with a bit of full fat solder helped with the heat transfer and suction on the (mostly) multilayer boards.
If you have one of these test sets and are experiencing odd problems, I can recommend the cap replacement procedure, but unfortunately there aren't many short cuts to replacing electrolytic caps.
Home
Help
Search
Login
Register
