PCB of garage door opener failed: Which PIC is this?

Hi there,

I have a garage door opener named "Liftboy SMD 3200" which was installed into my garage back in 1990 (in Germany). I couldn´t get any information about this garage door opener on the net. The motor control PCB of it just failed this week. I suspect either any capacity or the voltage regulator to be the culprit. Does anyone know the manufacturer of the PCB shown under

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?

Unfortunately, the 40-pin PIC´s type isn´t readable under the sticker at all ´cause its surface seems to have been scratched off under the sticker by the manufacturer of the PCB. Yagh. Which PIC is it supposed to be? There is a Quartz which reads "4.000 SUNNY 7624".

Moreover, the same applies to the 16-pin IC: It´s surface seems to have been treated by the manufacturer of the PCB, i.e. the exact type has been completely scratched off on purpose as well. :( Is there any way to find out which IC it might be?

Please advise.

TIA, Joachim

Reply to
Joachim Wunder
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Reply to
Homer J Simpson

Unfortunately not. I already phoned them up today. And, no, they are not the manufacturer of this Liftboy SMD 3200. Any other ideas are highly appreciated.

Reply to
Joachim Wunder

Any other info on the labels? Country of origin?

Reply to
Homer J Simpson

Judging by the amount of heat that has been pouring off that regulator, and discolouring the board above, the first thing that I would be doing is removing that chip that says " VOH " on it from its socket and cleaning the pins. What exactly is the board doing wrong ? Assuming that device is a PIC, in general, they are very reliable.

Arfa

Reply to
Arfa Daily

No, unfortunately not. Well, on the backside of the PCB is printed "PRO6101-28" in one corner. That´s all. Well, the garage door opener was installed into my garage from a small company called "Schiel" from northern Germany. Well, they said that the manufacturer went bancrupt a couple of years ago and that they don´t have any spare parts or information about this product of mine no more. :( Well, and the garage door opener "Chamberlain" said to me that "Liftboy" might have been an US based manufacturer who went bancrupt a couple of years ago, but they were not sure about it. I called up Chamberlain not only in Germany but even in Illinois, US.

Reply to
Joachim Wunder

Well, ok, cleaning the 16-pin IC´s pins will be easy, and I´ll do so, of course. Well, from my first investigations the 40-pin PIC is very likely to be an Intel 8748 or 8749. Question now is what current PIC is still compatible to this old-fashioned one.

The whole board should control the 220V~ motor of the garage door opener, but nothing happens no more. The board behaves like dead. Reason might be a 25W bulb which blew off just before the board didn´t show any reactions no more. The 25W bulb is connected in parallel to the PCB´s power supply.

Reply to
Joachim Wunder

If indeed this is a PIC or some other type of microcontroller, you cannot just replace it. It has to be programmed with the original code. Good luck acquiring that since most manufacturers set a bit in the device to prevent reading the program stored within.

The failure of the 25 watt bulb may be a clue. A bulb can momentarily create nearly a direct short when it fails. What voltage is this bulb? 220v or something smaller?

David

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Reply to
David

At this point I'd buy a whole new one from a reputable company but I know prices there are higher than here. It'll be a miracle if you can get any parts for this unless you can track down someone who used to install or repair them.

Reply to
Homer J Simpson

Yes, I am aware of the fact that I would need a PIC programmer and a new 8748 or 8749 PIC (I´m still not sure which one it really is). Pretty good question where to still get such a component from, I know,... is there any equivalent PIC which offers the same pin assignment and code compatibility of a 8748/8749? I know, even I doubt that, but I better ask in this group before giving up.

220V AC, as we have in Germany.

Joachim

Reply to
Joachim Wunder

Yes, I know, chances are low. Tomorrow I´ll try again at the small German company which installed it back in 1990.

Reply to
Joachim Wunder

Hi!

I think the large IC looks like an 8031/8051 microcontroller...these are a very popular, relatively low cost and highly available part. Are you sure the power supply is working correctly? Perhaps it suffered some damage or opened a fuse when the bulb blew.

One of these is ROMless, but I don't remember which one. What does the little pushbutton on the board do?

William

Reply to
William R. Walsh

Sometimes they know a guy who knows a guy . . . . .

In a company I worked at, we had 4 injection moulding machines of poor design and reliability which were made in Austria by a company that went bankrupt. It was a PITA keeping those suckers going. We had to reinforce various parts with welded bracing.

The Swiss ones (design styling by Italians) we replaced them with were expensive but were a joy to work on and would take anything you could dish out. Watching them mould a 2 litre bowl every 4 seconds was almost frightening to see.

Reply to
Homer J Simpson

Right. I will give it a last try.

Hey, could you do me a favour please? What was the name of the company in Austria? That all rings a bell to me: Company "Schiel" in Germany still believes, that my garage door opener´s motor control PCB was made in Austria as well. And when I look at the backside of the PCB, oh man, the soldering.. like if a 5-year-old child would have done some work on it. Various parts with welded bracing as well. Ufff. I will need some real professional soldering work to get all of that crap corrected anyway.

I see.. I am not yet decided, but may do so soon if that hunting for the manufacturer won´t come to an end soon.

Reply to
Joachim Wunder

Well, if I recall it right, then the 8031/8051 microcontroller comes in plastic package and doesn´t has an EPROM memory like the 8748/8749, right? So, I tend more for my PIC to be one of 8748/8749, but correct me if I´m wrong.

No fuse on the whole PCB unfortunately. And, yes, the power supply still outputs a stable 12V DC.

The little pushbutton normally helps the installer to testdrive the garage door open and closed. That´s what I know for sure about this PCB.

Joachim

Reply to
Joachim Wunder

It was over 25 years ago. It might pop back into my head but I doubt it. However these companies had nothing to do with garage door openers.

You could design and build your own replacement, or maybe you could buy and adapt the parts from a different model.

Reply to
Homer J Simpson

The IC will have custom firmware on it so you won't be able to replace it. Chances are unless the regulator has failed in a short circuit and caused the voltage to rise, the chips are probably fine. Check to see if the filter capacitor is shorted, I recently repaired an old Volkswagen ECU that had a shorted electrolytic capacitor filtering the 5V output, resulting in a dead car.

Reply to
James Sweet

Hi!

Hmmm...checking the Intel datasheet for the 803x/805x family shows that some of them (8051/8052/8751) do have onboard ROM program memory. At least one UV-eraseable version also exists.

Any packaging could be possible, given how many different companies have produced these parts over the years. Intel mentions a "CERDIP" package in their datasheet, which I would take to mean "ceramic DIP".

Another thought just occurred to me...and maybe it occurred to you as well. Did you pull the chip and check the bottom of it to see if there might be anything printed there?

William

Reply to
William R. Walsh

Exactly what markings are on the ?TO220-ish device below the small PCB? If that is a 3-terminal reg, I'd be checking it out as well.

Reply to
rebel

It seems to me that this is all getting a bit over-complicated. Why would a simple device like this even need a micro-controller ? Some years back, it was fairly common practice to put chips like this onto boards, that actually did nothing. Literally just there for show to make the item look worth the money that was being charged for it. Anyway, it seems that there is an obvious transformer, reccies, and a smoothing cap. Is that where you are measuring the 12v that you mentioned ? The very hot looking TO220 device next to the smoothing cap is 99% certain a standard 3 pin monolithic regulator IC, and I would guess that it's almost certainly a 5v one, so do you measure something like 12v, 0v, 5v on its pins ? If you do, do you have a 'scope ? Can you measure any clock activity at that crystal ? Beyond that, without a detailed knowledge of the functionality, and schematics, it's pretty much impossible to come up with a valid test strategy, that's likely to result in a repaired board.

Arfa

Reply to
Arfa Daily

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