JP1 Remotes

sdude · Joined: 18 Dec 2004 Posts: 9

Hi,
after quite a long time working without any problems my One For All 6 ( URC-7562 ) began to run in trouble.

First the key-presses were send with a little delay (0.5s)...

After replacing the batteries that problem was gone, but now its impossible to learn new codes via the 975 code... After pressing MAGIC, the led flashes twice, but after 975 the led flashes just ones, not twice as descibed in the manual.

That worked for me before, is the rc broken?

A reset with 980,981 didn't help either.

After searching in thid forum a additional hint: After reinserting the batteries I get just one long blink of the LED!

Thanks,
sdude

johnsfine

sdude · Joined: 18 Dec 2004 Posts: 9

Mark Pierson

johnsfine · Posted: Sat Dec 18, 2004 3:27 pm Post subject:

There are good instructions for taking it apart here:

http://www.hifi-remote.com/jp1/disassemble/index.shtml

Once you understand how those "snap latches" work, you can get it apart without breaking it.

The eeprom is a tiny IC with 8 connections, 4 on one side and 4 opposite (I think on one side all four are connected together).

The problem is likely to be on one of the traces connected to that IC, so examine them as far as you can visually trace them from that IC.

The Robman · Posted: Sat Dec 18, 2004 3:35 pm Post subject:

Personally, I use a very small screwdriver to pop open the first clip, then I slide a plastic putty knife into the opening and slide it around the edge of the remote popping open the rest of the clips. I pick up the putty knives at the local hardware store for $1 each. If you don't want to bother getting a knife, use an old credit card instead.

Once you've cleaned and/or dried the PCB, I would recommend putting it back into the lower half of the casing, then put the batteries back in and lay the button sheet onto the PCB. Finally, do a 981 reset. If you get 4 blinks, you can close up the remote as it's working again. If you still get 2-short, 1-long, you'll need to take another look at the PCB.
_________________
Rob
www.hifi-remote.com
Please don't PM me with remote questions, post them in the forums so all the experts can help!

sdude · Joined: 18 Dec 2004 Posts: 9

Hi,

after checking the pcb I found nothing that could cause an short or similar.

And, if the eprom would be complete defect, how is it possible that it stores the codes for tv,vcr?

Maybe a part of the eprom is defect, so that no extra key could be learned?

Mhhh,

sdude

johnsfine · Posted: Wed Dec 22, 2004 8:08 am Post subject:

sdude · Joined: 18 Dec 2004 Posts: 9

OK, but if it is using RAM for the codes the rc would loss it when removing the batteries, right?

But that doesn't happen. I removed the batteries, pressed some keys till no more LEDs were flashing.. Waiting a while, put the batteries back in again, and the codes a still the ones I teached in.
OK, maybe there is an extra buffer for the RAM, in that case the only thing could be replacing the eprom chip.
I don't want to throw it away right now, it's about 45,-€ here...

Well, maybe I can find a source for the ic in germany...

Thanks,

sdude

The Robman · Posted: Sat Dec 25, 2004 5:53 pm Post subject:

There is a capacitor in the remote that keeps the ROM alive for about 30 minutes after the batteries are removed, but pressing buttons should have discharged it.

Bottom line is this, we don't know exactly what's wrong with your remote, but something's obviously not right. I would suggest that you check for connectivity between the EEPROM and all the places it should go. Pins 1 thru 4 and pin 7 should be grounded, and pin 8 should go to the positive pin of the big capacitor. Pin 5 should be connected to a small capacitor that is in turn connected to pin 8. Pin 5 also goes under the glob to the MCU. Pin 6 should only go under the glob, so there's not much validation you can do there.

(This is all from "off the top of my head" memory, so forgive me if I've mistated any of the EEPROM connections)
_________________
Rob
www.hifi-remote.com
Please don't PM me with remote questions, post them in the forums so all the experts can help!

sdude · Joined: 18 Dec 2004 Posts: 9

I will try to find out about the connections/traces from eeprom to the places you mentioned.

Unfortunately I don't have an oscilloscope here to see if there is something that looks like i2c communication.... maybe I can get one the next days.

I found the eeprom at a german distributor, just 2,50€. If nothing is wrong with the traces, I will give it a try.

Thanks,

sdude

sdude · Joined: 18 Dec 2004 Posts: 9

Hi,

I checked all traces from the eeprom, looks all good.

Then I replaced the eeprom with a new one, but the rc reacts as before.

Well, I guess that there is no further possibility to find that bug, right?

Anyway, thanks for your help,

sdude

EDIT

WOW! Before throwing the rc in the garbage, i tried a *994 ( found with google ) ...... AND :
*981 gives me 4 blinks!!!!! Thats nuts?!?
Kill me, but I don't know the exact keys I pressed after the 994..

Now I can learn keys etc with 975, everything is OK.
Maybe this could have been the solution before placing a new eeprom on it Rolling Eyes

OK, thats it, maybe this helps someone else in the future, thanks again,

sdude

The Robman · Posted: Thu Jan 06, 2005 9:45 am Post subject:

Well, I can't offer you any good reason why doing a keymove (ie, 994) would re-enable the 981 reset, but hey, if it works, who cares, right?
_________________
Rob
www.hifi-remote.com
Please don't PM me with remote questions, post them in the forums so all the experts can help!

sdude · Joined: 18 Dec 2004 Posts: 9

That's right, and I'm glad that I saved ~50€.

Another thing is that after learning a lot of keys from original rcs with 975
I now have again the problem that it takes up to 0,5-1 sec after pressing a key the code is send.... is that a known problem?

sdude

EDIT

And, here we go, after one day i'm back at the start.... the rc reacts again like described in my first post. The 994 did not help. After going nuts I tried again an 981 with fresh batteries and .... 4 flashes ???!!!!
OK, maybe this is causing all my trouble?

Tatanka · Joined: 07 Jan 2005 Posts: 16 Location: Argentina

Sdude,

Is your RC working?. I have a similar problem with my URC 8811. I get the four flashes after the 981 reset. However, the RC does not learn any keys with the 975 code. I tried removing batteries, changing them and even shorting out battery terminals, but still no sucess. Any suggestions?

Thanks in advance.