RTC Replacement

[avctech]

Never seen that one before :shrug: like its in some test mode or something. Is the floppy light still flashing ?

Nope, nothing. Power light is on and fan is going, but that’s it. I’ve seen this screen before a long time ago but I can’t remember what caused it. I thought it might have been when the RAM card wasn’t seated correctly but I have checked that. Maybe RAM is faulty?

[exxos]

what happens if you take out the ram card ?

[avctech]

No change....it’s all a bit odd :roll:

Will trace all my pins in the NVRAM again, make sure something didn’t come loose, but I am sure it’s not that.

[exxos]

what happens if you unplug the rtc ? Or leave battery out for a couple mins to reset it.

[avctech]

Left the battery out all day, but no change.

I can’t remove the RTC as I didn’t use a socket.

Rechecked all the connections and everything is fine.

I did notice on checking ground that there is a short connection from pin 12 to ground, but then nothing. Removing the probes and reconnecting gives me continuity for a second then nothing.

Also I discovered that when power is on, there is 0.7v on pin 12, surely this can’t be right?

[exxos]

Can you scope the main clocks on the CPU etc ?

[avctech]

Unfortunately I don’t have the equipment to do that ☹️

I think this may be a project for another day 😊

Thanks again for all your help :thanksyellow:

[ErdaWilt]

Hi...I found the battery was not making steady electrical association with the negative contact plate under the battery. This in light of the fact that the epoxy form made by the old battery kept the new battery from connecting. I settled this issue and now in any event I absolutely never get a totally clear screen on bootup. Each time I boot the PC it experiences the interminable circle cycle I portrayed previously.

[maxun]

Hi,

I purchased a new LP RTC replacement NVRAM Clock chip from your store. I received it and installed it the other day. Unfortunately it didn't work and the falcon was not booting. I tried the ALT+SHIFT+RSHIFT+UNDO but that didn't work either. Since I installed the socket I removed it and re-installed the old chip and the falcon started booting again. After that I went ahead to try to diagnose the problem; Continuity on the pins were fine, 3 volts was correctly coming from the battery, however upon testing the crystal with the oscilloscope I found that there was no signal. Is there anything else I could try?

Thanks

[exxos]

As long as the module is making proper contact in the socket, and the battery is inserted, the Falcon should boot up as normal. The osc might be very low voltage, so you might not see it. Or the default state of the module might have the RTC turned off, that has caused some problems with some RTC software, but wouldn't prevent the falcon from booting.

Unfortunately there is some problem with some falcons which prevents different modules from working. This is not simply just my modules, or other people's modules, it can even happen with placing with another original RTC chip. To my knowledge nobody has investigated why this happens.. 99% of the time module failure is bad soldering on the socket or track damages.

Other than sending me your motherboard to diagnose, I cannot not really suggest anything much. It could take some time to diagnose the problem. My only suggestion would be to change the capacitors in the reset circuit as it is the only thing I can really think which may cause problems, but it is literally just a guess.

EDIT:

I assume you used the LP socket from the store and I think the middle plastic has to be removed also.

Also a similar thread here where seems to be problem with the socket. https://www.exxosforum.co.uk/forum/viewt ... 7&start=10

There was also this thread https://www.exxosforum.co.uk/forum/viewt ... t=37#p2479 but that capacitor is included on the LP boards anyway.