I keep getting the H-4 Code I replaced the bulb and still keep getting call backs after a few days of H-4 again? Anyone have an idea whats going on here? I went ahead and rebuilt a whole fuser unit and replaced but still got the call back again? To be honest I have not put a brand new heat lamp in it as I'm tring to use up all the old parts I have. I dont think all my bulbs could be bad? It clears and the bulb lights up. Any help and thanks in advance.
Wow... look at the call above yours... SF 7300. H3 returns. Might be a similar problem. Have you read the post way down below for "Old Sharp Techs"... it might shed some light. H3 and H4 are not too dissimilar on the old Sharps. Check thermistor and clean it if it's got build up first, reset then wait. If it comes back run a test on your Thermistor if you haven't already. Then the next possibility is.. (drum roll) the TRIAC. (Sounds like a grade be horror flic) Attack of the TRIACS!!
I'm sure we old boys will jump all over this one too.
God Speed! Pete
I think tric also. Check solder joints. Does the bulb blink in sim? Is it popping a breaker or fuse? Is the fan working. They had a trick with putting duck tap above it on the frame to help keep the heat from causing issues. Did you throw a meter in the outlet? Maybe it is just old age...
I went ahead and rebuilt another unit and headed to the call. I cleared it and it was fine. I asked the customer does it get real cold in the room where the copier is located? Yes. I explained to him about it might be taken to long because of the extream cold to ready up. So I think the mistery is solved. Thanks and will see what happens next. Whats a good sharp to upgrade this with?