UEC 4121 reboot issues

[Softek2]

is there anyone reading this post had and managed to repair the consistent reboot issues that seem to manifest themselves on the (CPU pcb)?. I now have half a dozen boxes with this problem. Before Altech decided to evaporate the country they offered to repair the (older) decoders but it was not economic to do so in most cases. Both postage and downtime played a significant role in decisions made. I can use the power supply pcb's etc for parts but would like to see if the processor boards can be repaired. Being lazy; made me think of an EFIL repair first.... I'm sure someone has re-invented this wheel before. Thanks in advance.

[hos here]

Suggest you contact Deen at Access 2 Qld 0731589693 or for their 'retro fit' 12 volt power supply to fit UEC 4121. I have repaired a number of these UEC units and it stops 'random reboot'. UEC know of these PSU's but won't tell you about them.

Cheers
Hos Here

[hos here]

Sorry that web site is a dud.
Try :


Cheers
Hos Here

[Softek2]

Thanks hos here; but it is not the PSU at fault. By substitution the fault remains on the CPU board. I suspect a few electros on the 3V rail but not sure. I will do some more digging (in my spare time). I was asking in the hope others who had this fault may have an answer. If the fault is just a dry joint or similar it would be easy enough to fix, if however the fault is more sinister, maybe a surface mount chip or such, then it is probably beyond my capacity (& sight) to carry out any worthwhile repair anyway.
Thanks for your input.

[Softek2]

Hi All,

Just an update on my quest. After much digging about on the CPU PCB I found a slither of solder which through time (heat & cooling) managed to short one of the 3v3 rails. It did take some finding (without circuit) but bloody obvious in hindsight. The first one three weeks on and off to locate and repair then about six minutes (start to finish) for each then on. I wonder how much A@T#c made from every repair? as it was a manufacturing fault not component failure. I guess we will never know.

[mtv]

Good find and one to look out for with others having similar symptoms.

[puca]

any pics so I know what to look for cheers both my boxes do this and damn annoying

[sublib25]

Any chance you can point is to where the fault is?

[Softek2]

Sorry everyone, Late to reply as things have been busy. I did not document my problems as I thought there was little interest. If you look under the (metal) electro in the pic (on the under side of the PCB) you will see a single track running parallel with another and joined by a blob of solder. It does not look out of place at first but keep looking it will become obvious. I didn't find the fault after several hours of pondering it was my TA who decided to look for something unusual after being told about "dry joints" etc. He located it (and other suspect) joints after about ten minutes. He is not educated in electronics and does not know what to look for as such. Hope this gives everyone here a bit to go on. I will document the next on and post more pics. As for me ; back to 20/20 hind sight.