HP Forum Archive 10

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smoking hp85 Message #1 Posted by andy on 10 Feb 2003, 10:05 a.m. When I powered up my hp85 this weekend, the following happened: 1. The tape light came on 2. A burning smell eminated from the back So I took the cover off and tried again. There are a couple of transformers near the CRT. One of them was smoking. Any advice? Thanks, Andy

Re: smoking hp85 Message #2 Posted by Mike Meyer on 10 Feb 2003, 10:21 p.m., in response to message #1 by andy Have you tried laying an HP-10BII across it? Sorry. Couldn't resist.

Re: smoking hp85 Message #3 Posted by andy on 11 Feb 2003, 9:11 a.m., in response to message #2 by Mike Meyer :) I don't have a 10iib but if i did... On a more serious note, I discovered that a capacitor downstream of the transformer had gone bad (it reads shorted). Hopefully the transformer is still good (even though it was smoking, it still reads good) and replacing the capacitor will get it working. Andy

Re: smoking hp85 Message #4 Posted by Michael Meyer on 11 Feb 2003, 9:21 p.m., in response to message #3 by andy Nice find. There are many here who know more about electronics than I.... but I agree. If the voltages look right, the transformer should be OK. I wouldn't power it up and then go out to dinner, though... Michael

Re: smoking hp85 Message #5 Posted by andy on 11 Feb 2003, 9:57 p.m., in response to message #4 by Michael Meyer I replaced the bad capapcitor and re-installed the transformer. I accidentally put the transformer in backwards. Belive it or not, it only blew the main fuse. After properly re-installing the (still good) transformer, my hp85 is up and running again!! :^) Now onto replacing the little gummy wheel so I can get the cassette drive working too. Andy

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