The permanently attached Barco ICP battery

[Jay Glaus]

I was changing batteries on some Barco ICPs and got to thinking. That permanently attached battery that once it goes dead the board is shot... how hard would it have been for Barco to put two batteries in parallel so you could change them out 1 by 1 and not have the issue of the board dying when that battery died. Kind of what GDC did in its IMB’s.

[Carsten Kurz]

Well, first of all - Barco didn't make these ICPs, but Texas Instruments. Why they chose a soldered in battery instead of one that can be swapped - no one knows for sure.
On Barcos own ICMP (and ICP-D), they did build-in two sockets for a swap-over. Which is absolutely necessary, because the ICMP battery only lasts about 5 years.

There have been discussions here about proper implementations for low current circuit batteries. Some say that sockets may create problems with these very low currents, and that a solid solution needs to be soldered in. The trouble is that a battery that only keeps an arbitrary clock (like the second cell on the ICP) is not a critical component, as the clock can be set again in the field. But a certificate following the DCI security concept can only be restored at the factory. So the idea might be that it is safer for the assumed lifetime of the product to have a soldered in battery, even if that means that the cert will be lost for sure AFTER the assumed lifetime of the battery expires. I think at the time this board was developed, they thought it to be okay if a 5000US$ board has a projected lifetime of 10-12 years, even if it's death is stupidly caused by a 1US$ battery.

[Jay Glaus]

Yeah I know TI did the ICPs I guess I just worded that wrong.

Technically I guess with two batteries you could have unsoldered one, soldered another in and checked for continuity and hoped you soldered good, it’s just surprising they didn’t plan for longer longevity. But I’m used to 35 mil, where projectors from the 40’s and 50’s still ran. When you think about it, if you have a computer for 10 years that’s a long time, and I guess for digital you have to think that way. I still do have my MacBook Pro from 2010 though and she runs like a dream

Plus they always say for car companies they make more money on parts than they do actually selling the parts, maybe that’s true with more things than parts.

Not talking down on Barco or TI, just thinking out loud...

[Steve Guttag]

The battery is actually more than $1USD...I have no problem with the solder in battery. But why not two such locations. After the prescribed time, solder in the new one, cut some wire links to unlink the two and then have a 20-year board. If it is still going that long, with the links cut, it would be safe to unsolder/solder in yet another replacement and go for 30-years.

Oddly, NEC copied the ICP so much on their FMT board that they too have the same solder-in battery for the certificate and socketed battery for the RTC.

[Jay Glaus]

I’ve always thought about tracing the circuit and temporarily connecting another battery in parallel then removing it after the change, just never been brave enough to try... and never had a working ICP I was comfortable throwing away if I killed it in the process.

[Leo Enticknap]

Again, there have been discussions on F-T and elsewhere about the feasibility of connecting a temporary 3V supply while the certificate battery is swapped out on a TI ICP. But as you point out, it boils down to the fact that you have to risk sacrificing a functioning part that would cost $5K to replace - and furthermore, one that the projector will not work without - in order to attempt the experiment. I hope that one of these days, a well heeled customer will opt to replace a 10-year old ICP that still works preemptively, at which point I'll have one to do the experiment with. But until then, I am simply advising my customers with older Series 2 projectors that it's a case of when, not if, the ICP bites the dust, and that they should budget to have to spend that money on replacing it at any moment, if they do not plan to replace the projector in the near future.

[Steve Guttag]

I think we'll phrase it to the effect of: This board is to be changed and we have one with us. If we are able to change the battery, the cost will be the part plus time. If not, you're buying the replacement board, as previously discussed. So, as far as the customer is concerned, they are no worse off than they were and quite possibly better. Once we know if we can successfully do the operation (or not), we'll know the likely outcome. I'm hoping that we can because it is silly for such a small and inexpensive part to cost effectively a lot of money.

Really, I think it is shameful that the OEMs don't offer an ICP RX program for just changing the batteries.

[Marcel Birgelen]

Maybe none of the OEMs is offering a reasonable trade-in/swap program because TI is itself dropping the ball on handling the situation. If I remember correctly, it was discussed before that only TI themselves are capable of re-initializing an ICP with a lost certificate.

Also, the soldered-in design, really is no excuse, it's a cheap shortcut, which could even be qualified as a genuine design defect if someone would be willing to take this to court. If a reliable connection with those pill-shaped batteries is a problem, there are other battery form factors that allow for both a reliable connection and replaceability. But even a two-pin header or other means of connectivity for a temporary power source during a replacement procedure isn't provided. It's telling how Barco went with a different design for their replacement ICMP and ICP-D...

[Randy Stankey]

I don't have a problem with a soldered in "keep alive" battery because if there is some accident where a socketed battery comes out of the socket, all is lost and recovery would be difficult and expensive if not impossible. Soldering the battery in prevents accidents and makes it harder for wankers to mess things up.

However, I think it would be better to have either a soldered in battery plus a socketed battery, in parallel. That way, you have a chance to install a new battery in the socket or replace the soldered battery while the one in the socket keeps the boards memory alive.

If security is a concern, there could be an empty socket with a cover on it soldered in parallel. It could be an "open secret" for technicians to use.
They can either slip a battery into the empty socket in a do-or-die situation or put one in so that they can change the soldered battery at their leisure.

[Marcel Birgelen]

Imho, A simple sticker: "WARNING! Do not remove!" should be sufficient for any "wanker" to be sufficiently informed. If said wanker or wankerette removes the battery anyway, you're probably dealing with the kind that doesn't care about "High Voltage" warnings too.

[Randy Stankey]

The only warning sticker you should ever need:

Warning Sticker.jpg

[Harold Hallikainen]

I think the dual battery holder idea would work IF the contacts in the battery holder and on the battery were gold plated. However, they all seem to be nickle plated, and nickle on nickle contacts are terrible for low current. I talked with the manufacturer of coin cells and coin cell holders about the issue. They did not consider it a problem. We lost a lot of certificates before we started soldering in batteries

[Carsten Kurz]

I think no manufacturer of such a board would actually plan to have a cert battery unsoldered as a regular service task. Also, they may have wanted to make sure that, if two batteries are on the board, no one takes out the one that kills the cert, so, there are probably a few good reasons why they did it that way.

ICPs are not manufactured by TI themselves, but a TI subcontractor. So, it's not between just the OEM and TI to reprogram a cert.

A colleague here in germany tried to unsolder his ICP cert battery, but at the time he wasn't aware that he needed an isolated soldering iron. So he lost his ICP, but that dead one now is his learning prototype, as he has more ICPs of the same age and will try it with them as well. The critical cell voltage is around 2.5 volts. I have measured a couple of older and younger ICPs recently, and it seems there is a huge span in cell life. I have seen a 10 year old ICP cert cell that still has 2.89 volts on it (and that machine is powered down completely for around 16 hours each day). I guess I would start thinking about replacing the cell when it reaches 2.6 volts. Measuring the cert battery voltage during regular maintenance is not hard to do and relatively safe.

- Carsten

[Marcel Birgelen]

What's wrong about a CAT1600-style battery like on the CP850? Those contacts aren't gold-plated either and although the CP850 has had many issues during its lifetime, losing certificates isn't one I've encountered yet.

I don't think you can expect your batteries to be gold-plated, but for a device with a ticket-price of a few grand, gold-plating the battery contacts shouldn't be so much of a deal.

[Leo Enticknap]

Imho, A simple sticker: "WARNING! Do not remove!" should be sufficient for any "wanker" to be sufficiently informed.

Unfortunately, the (metaphorical, obviously - I don't mean the literal one) definition of a wanker is someone who does not practice any sort of common sense, and almost considers it a badge of honor to refuse to do what common sense suggests in any given situation. This mindset goes beyond simple not caring: it holds that the wanker knows better than whoever put the warning sign up. Wasn't it Churchill who made a comment to the effect that improvements in idiotproofing inspire idiots to upskill themselves? Can't remember the exact quote, but that is the gist of it.

I think we'll phrase it to the effect of: This board is to be changed and we have one with us. If we are able to change the battery, the cost will be the part plus time. If not, you're buying the replacement board, as previously discussed. So, as far as the customer is concerned, they are no worse off than they were and quite possibly better.

The problem is that the "this board has to be changed" moment is not accepted by the customer as having arrived until the board has failed, at which point the thing is basura anyways. Last week I had a call about a DP2K-20C manufactured in July 2010 that, per our records, still has its original ICP. The problem with that projector is that the SMPS has failed, but after checking our records I suggested to the end user that they may wish to replace the ICP as well, pre-emptively, because it can't have long to go. "Heyllllll, no!" was the gist of their response upon being told the price of a new ICP. Their existing one still works, and they'll continue to use it until it breaks. Once that happens, it's useless for any battery replacement experimentation.

I think the dual battery holder idea would work IF the contacts in the battery holder and on the battery were gold plated.

The Barco ones in the ICMP and ICP-D are very strongly sprung: you absolutely have to use a drinking straw (or other insulating device) over the positive terminal when pulling a battery out, because if you don't, the chances of it hitting the negative terminal below once the battery is clear are quite high. In contrast, the ones on the Dolby cat745 and Doremi Dolphin are thin metal and quite weakly sprung. They bend easily, which might account for the high failure rate: the negative terminal no longer makes a good contact after the new battery has been reinserted, because it was deformed slightly by the replacement process.