latest synch rebuild

[clockace]

hi all, i have just gotten my latest mkI/II going. the last one i have. it was quite a challenge. did not lite at all when i got it from howard. under light for a few wks it glowed dimly, but not coherently. the display was all jumbled up with missing segments. i thought new qc first. installed that and no improvement at all. checked sc, ok. then i figured i will have to remove all gel[it was the good kind, not snotty] and i really wanted to leave most of it there. uh oh. under the sc rusty corrosion. some of the legs on the chip were gone. what to do? i had a pc board that was already trashed by corrosion. several of the transistors were gone, but the chip looked good. i unsoldered all of those legs[there are 24 of them] on the one i was working on. then i unsoldered all 24 legs on the one i hoped was good. then i resoldered all 24 onto the good pc. put the power to it and IT WORKS!! discovered the #7 had a segment on the bottom. i had shorted 2 of the segment drivers with my clumsy solder job. i cleaned that up and now it works fine. has been set and under a light for charging. thx howard. counting my original repair on my own mkI/II i now have gotten 8 out of 9 going. howard, i need more s/s tops and duchess bracelets. i am pumped over the results of today's efforts. also it is good to see howard's posts again. the synchronar forum needs that. regards, peter

[rewolf]

i unsoldered all of those legs[there are 24 of them] on the one i was working on. then i unsoldered all 24 legs on the one i hoped was good. then i resoldered all 24 onto the good pc. put the power to it and IT WORKS!! discovered the #7 had a segment on the bottom. i had shorted 2 of the segment drivers with my clumsy solder job. i cleaned that up and now it works fine.

That was a tough soldering job for sure. I don't know what equipment you used, but with a "normal" soldering iron it deems me almost impossible - the more impressive if you did it that way (I'd rather use hot air soldering).

[clockace]

rewolf, i used 2 different irons. one is a standard 30-35w plugin and the other is a handheld rechargeable with a microtip. it is made by the wahl clipper corp in usa. i am not sure of the watts, but it heats up to about 700 degrees in about 5 seconds. i also used solder wick to remove the bulk of the old solder on the chip i planned on using. on the one i was replacing i just heated the chip leg and pried it up with fine pointed tweezers. that left enough solder on the board pads so i only had to press down on the leg and heat it with the microtip. as soon as the solder melted i removed the heat. i also cleaned the legs with a fiberglass pen so the solder would adhere well. where in germany are you? my wife was born and raised in wurzburg. i have not heard of hotair soldering. regards, peter

[rewolf]

where in germany are you? my wife was born and raised in wurzburg

In the very south, Ravensburg, near the Lake of Constance (Bodensee). But my father was born and raised in Marktbreit, 20km from Würzburg, so he's also a "Frangge" like your wife