small problem with Gemini V1.05 brains

[h0ughy (David)]

well i keep putting in new batteries only for the computer to loose the cmos settings after i turn it off. when i turn it on I can set the location with the GPS and the mount i manually set to titan50, it takes two goes but it remembers - but if i turn it off and wait 5 min it looses the lot. its becoming a PITA. I know its not the batteries i have been through 4 different packs of brand new energiser and duracell CR2032.

So what may be the problem?

[mithrandir (Andrew)]

David, are you sure the battery is located correctly and the clip is OK? See if holding the clip down while turning off and disconnecting power, waiting 5 mins and powering up makes any difference. If it does, try a metal shim on top of the battery.

One question. Are you using the hand piece or running it from Gemini.net? Gemini.net might be downloading a default config. You have to get it to save a valid config before letting it download on connect.

[h0ughy (David)]

Originally Posted by mithrandir

David, are you sure the battery is located correctly and the clip is OK? See if holding the clip down while turning off and disconnecting power, waiting 5 mins and powering up makes any difference. If it does, try a metal shim on top of the battery.

One question. Are you using the hand piece or running it from Gemini.net? Gemini.net might be downloading a default config. You have to get it to save a valid config before letting it download on connect.

no using the handpiece - i have set gemini.net for my observatory so when i connect it it does write the location etc of the obs to the handcontroller, but in this case i did seat the battery. i will take some macro shots of it this evening. to see if it looks fully seated

[wasyoungonce (Brendan)]

David

you have check the SRAM/RTC voltage, see here, should be above 2.8V. You probably already know this but low voltage is the usual suspect.

I can speculate the causes but best to have a reading of the VSRAM first before rabbiting on.

[h0ughy (David)]

Originally Posted by wasyoungonce

David

you have check the SRAM/RTC voltage, see here, should be above 2.8V. You probably already know this but low voltage is the usual suspect.

I can speculate the causes but best to have a reading of the VSRAM first before rabbiting on.

but i have put in a brand new battery? No idea how i measure this without killing something - not my skill set (I have no skill set )

[wasyoungonce (Brendan)]

Originally Posted by h0ughy

but i have put in a brand new battery? No idea how i measure this without killing something - not my skill set (I have no skill set )

Hi David

Check the battery clips are not distorted and losing contact. This can lose VSRAM etc. Other that that it really needs VSRAM measured to gauge the fault.

Other than a bad battery/battery clip, it could be a couple of things, mainly: bad Diode D1 (common fault); SRAM IC (another common fault); C8 (sometimes) or RTC IC (rare). Since D1 is a dual diode: one half feeds VBatt to SRAM/RTC cct when powered off.

+5V powers the other of D1 cct when switched on. This allows SRAM data to be stored by sensing the lower voltage, Vbatt, and come to life when it senses +5V (aka switched on). If you lose Vbatt/VSRAM then data will not be saved.

It's all to difficult to say with certainty what the issue is atm without measuring VSRAM. I have replaced SRAM IC's, D1's and RTC for similar symptoms (all different faults).

Do you have a friend who can wield an multimeter?

We all have skills...I for instance have no artistic talent yet yearn for such!

[h0ughy (David)]

Originally Posted by wasyoungonce

Hi David

Check the battery clips are not distorted and losing contact. This can lose VSRAM etc. Other that that it really needs VSRAM measured to gauge the fault.

Other than a bad battery/battery clip, it could be a couple of things, mainly: bad Diode D1 (common fault); SRAM IC (another common fault); C8 (sometimes) or RTC IC (rare). Since D1 is a dual diode: one half feeds VBatt to SRAM/RTC cct when powered off.

+5V powers the other of D1 cct when switched on. This allows SRAM data to be stored by sensing the lower voltage, Vbatt, and come to life when it senses +5V (aka switched on). If you lose Vbatt/VSRAM then data will not be saved.

It's all to difficult to say with certainty what the issue is atm without measuring VSRAM. I have replaced SRAM IC's, D1's and RTC for similar symptoms (all different faults).

Do you have a friend who can wield an multimeter?

We all have skills...I for instance have no artistic talent yet yearn for such!

yes artistic talent would be nice - missing from my gene pool

so if it is one of the other things - where would i get them repaired now?

[wasyoungonce (Brendan)]

David...

I have a full list of Gemini 1 spares on Hand and have repaired ~a dozen units so far. I suspect D1 or SRAM IC...done a few of those.

I cannot say if Peter Ward is repairing Gemini's, you would have to ask him.

[allan gould]

David
I have recently had my Gemini handset repaired by Brendan.
Excellent service from him and I could not praise him more highly.
Knew exactly what was wrong from a description and fixed it promptly.
I would not hesitate to send my whole Gemini setup to him for evaluation and fixing.
Would I lie to you?

Allan

[h0ughy (David)]

Originally Posted by allan gould

David
I have recently had my Gemini handset repaired by Brendan.
Excellent service from him and I could not praise him more highly.
Knew exactly what was wrong from a description and fixed it promptly.
I would not hesitate to send my whole Gemini setup to him for evaluation and fixing.
Would I lie to you?

Allan

yes i think i will do that I trust you as far as that Scargo will travel

[h0ughy (David)]

Originally Posted by wasyoungonce

David...

I have a full list of Gemini 1 spares on Hand and have repaired ~a dozen units so far. I suspect D1 or SRAM IC...done a few of those.

I cannot say if Peter Ward is repairing Gemini's, you would have to ask him.

he did repair the switch on the module a few years back

[wasyoungonce (Brendan)]

Hi David, PM sent.

I'm guessing this is the PCB version with the Slide switch (these switches were prone to some fails, although I have replaced on of the newer switches as well, quite odd!)....although it doesn't matter what type of PCB.

edit:
Many thanks Allan, I do appreciate the kind sentiments.

[h0ughy (David)]

be in the post this afternoon

[wasyoungonce (Brendan)]

No Problems David. If you have GEMINI ASCOM.net profile for your system, you can send me, I can upload it prior to dispatch.

[h0ughy (David)]

on its way express overnight post

[wasyoungonce (Brendan)]

Ok all fixed looking good just doing final tests, No need to go overboard with days of testing, all functions: Slew; Sidereal; park; RS232 & ST4 have been tested as ok.

Should dispatch late today but will notify.