Voyager - opening up - small questions please



#2

I've recently got an 11C that essentially is in excellent condition but needs a clean to make it near-mint.

I have searched and found instructions on how to open it up and what to expect but a few details remain which I need clarification on please.

The main area of dirt is behind the front glass. What has happened is that there is a small gap between the front metal and the glass on the top side of the glass. If you imagine there is adhesive between the two and pressure has been applied at some time in the past which has opened a gap.

Now, what isn't clear to me from the instructions and pictures for opening the machine is whether the front glass is attached to the top half of the case or whether it is attached directly on top of the LCD itself. In other words, when I take the top off, will there be a hole where the display goes in the top half or will there be a glass rectangle attached to the top case?

The serial number is 2143Axxxxx so it is a 1981 American machine and therefore, I suspect the display assembly is separate from the keyboard but can this be confirmed from the serial number before I open it up? I am very anxious about doing this for obvious reasons so want to make sure I know exactly what to expect before I commit.

Concerning the rubber sheet between the keys and pcb, does this come off cleanly or should I expect resistance either through adhesive or the nature of rubber and time? Is there any danger I can actually damage or rip it?

Finally for now, the keys themselves - do they just sit in the holes in the front case and drop out if inverted? I would like to separate the front case completely for cleaning in the edges round the front metal panel.

Maybe I am making a fuss out of an easy process but with the value of these machines and the basic condition this one is in, I would be livid with myself if I messed up. For someone with basic handy-man skills (but all the right tools), is this a safe job or am I opening myself to disaster?

Thanks very much for any help and advice here. This isn't a job I would tackle without getting some guidance and support!

:)

Mark


#3

Mark,

I took apart an 11C a long time ago. I'll try to provide some information from memory.

Quote:
Now, what isn't clear to me from the instructions and pictures for opening the machine is whether the front glass is attached to the top half of the case or whether it is attached directly on top of the LCD itself. In other words, when I take the top off, will there be a hole where the display goes in the top half or will there be a glass rectangle attached to the top case?

Sorry, I do not recall. I never put mine back together, if I can find it I will check and let you know.

Quote:
The serial number is 2143Axxxxx so it is a 1981 American machine and therefore, I suspect the display assembly is separate from the keyboard but can this be confirmed from the serial number before I open it up? I am very anxious about doing this for obvious reasons so want to make sure I know exactly what to expect before I commit.

I'm no expert on the construction details of the various vintages. Again, if I can find mine, I'll tell you the S/N and how it is put together.

Quote:
Concerning the rubber sheet between the keys and pcb, does this come off cleanly or should I expect resistance either through adhesive or the nature of rubber and time? Is there any danger I can actually damage or rip it?

My recollection is that there was nothing adhering the rubber sheet to the pcb, it came off easily and it did not seem to be overly fragile.

Quote:
Finally for now, the keys themselves - do they just sit in the holes in the front case and drop out if inverted? I would like to separate the front case completely for cleaning in the edges round the front metal panel.

My recollection is that the keys just sit in holes and will drop out.

The above is probably not particularly useful without me verifying the information by finding my unit. I'll try to remember to try to find it. Unfortunately, either task (remembering or finding) may be beyond my capabilities!

The reason mine was never reassembled was because I had no confidence in my ability to re-attach the heat stakes. I read of various methods, including re-melting them, or gluing them, either of which would require some means to firmly hold things together while working on 40 or 50 heat stakes. Screwing things back together sounded appealing, but where to find 40 to 50 tiny screws of the proper specifications? So all the parts went into a bag, then into storage. Do you have a plan for reassembling the pcb to the front of the case?

Good luck,

Jeff


...


#4

Quote:
Do you have a plan for reassembling the pcb to the front of the case?

Here is a link showing a way to re-attach the heat stakes on a 15C using the pins of an old CPU (68030):
Original page in French and
Google translation

Edited: 19 June 2009, 5:20 p.m.


#5

Thanks for your help chaps.

I am rather worried now. This business with the "heat stakes" is the problem. On the page I found which showed an 11C being taken apart, there was no mention of this. It seemed that the PCB just lifted out. In effect, I was left with this impression of what happens:

1. You undo the screws and remove the back.

2. You peel off the rubber backing.

3. You lift out the PCB leaving access to the front glass.

However, with the heat stake problem, I clearly need to check this much further, especially given the number of them. I was moderately optimistic that I could do this job earlier today - now I am not!!!

Just as well I posted the thread and thanks for making me aware of this :)

Mark


#6

In the case of SN 2143Axxxxx, keyboard heat stakes are not an issue when accessing the display and window. The photos on this very website detail exactly what you will find inside your 11C. http://www.hpmuseum.org/tech10.htm

Once you remove the back and peel back the "black diaper" (an easily reversed process) you can lift out the logic module and clean to your hearts content.

Pulling the heat stakes off to clean is calculator homicide, don't make this harder than it needs to be which isn't hard at all...

Start with some canned air to remove the big bits (safety glasses mandatory) then hit with a light mist of glass cleaner, scrub softly with very soft brush, finish with a soft cloth to dry. Repeat if necessary and do a final finish with canned air.

Edited: 19 June 2009, 9:04 p.m. after one or more responses were posted


#7

Thanks Randy, I appreciate your help. I was confused by the heat stake problem as my initial research had suggested it wasn't a problem. Now with your confirmation of this, I shall go ahead with the job, perhaps this evening.

Mark


#8

The only HP's that can be "field stripped" for cleaning are the Classics and Spices. Everything else is heat staked or assembled in such a manner that external cleaning is the only option.

Some Voyagers get crud building up around the keys. This is due to small areas of exposed adhesive that attaches the aluminum legend plate to the plastic case front. Crap falls in, sticks to the adhesive on the back of the plate. Tough to really get clean in an absolute way.


#9

Right, well this has been done now and appears to have been successful. However, it wasn't without a major heart-stopping moment and only time will tell whether that turns out to be a problem or not.

A few points to note:

1. The pictures I found elsewhere which showed an 11C being opened with the internals attached to the back half of the case were rather misleading. When you undo the screws and take the thing apart, the internals are attached to the top half of the case and the back half comes off cleanly.

2. When removing the pastic envelope, I found that there was a slab of double-sided adhesive foam between the PCB and the envelope. This slab was nearly as wide as the PCB and about 1.5cm on the other axis. Obviously, this made opening the pastic envelope rather difficult and no matter how slowly and how carefully I did it, I couldn't help have a couple of small sections of foam detach.

3. There are two little springs you need to keep an eye on when removing the back. The longer one goes near the battery pack and the shorter on the right hand side as you look at the back of the calc.

4. To remove the main board and display section, I pulled off the four white "washers" that sat on the mounting pins and then removed the battery connectors. After that, it was a case of carefully lifting up the assembly keeping it parallel to the mounting pins and without putting too much strain on the flexi connecter area.

5. And this is when I had a horrible moment when I thought I had totally killed the machine. As I was lifting up the display assembly, the connecting area between this and the keyboard suddenly pinged loose leaving a strange looking connector on the display side. On the keyboard side, the pcb was completely clean with no sign of where this had attached. The only connectors I am familiar with have nice solid male/female mating so this strange thing looked broken to me and I couldn't see what hope in hell I had of lining it up again, yet alone fixing it back on the pcb.

6. Convinced I had killed the calc, I proceeded to clean everything up and pop the front glass back into its groove. Then I put it all back together again apart from the back case, stuck the batteries in and tried to operate it.

7. Nothing. Yep - killed it so I thought. However, I pushed down on where this connecter appeared to have broken and much to my huge relief, the keys started working and I could complete calculations.

8. I had intended to do much more cleaning but after this event, I thought I had better quit whilst ahead so put the screws back in and tidied up.

Thankfully, everything still appears to be OK. All the keys are working so whether that connector will be troublesome in the future or not, who knows.

Anyway, I've now got a better machine than I had but not as immaculately clean as I was wanting to achieve. Maybe another day.

Thanks again for all the help and advice that gave me the confidence to tackle this process.

Mark


#10

That little blue/black piece is an elastomeric connector a.k.a. a "zebra". These are very common in modern electronics and are most often seen used to connect LCD's. They need to be in compression to work, the back of the calculator provides the pressure points so without the back in place and a screw in the upper right position, the keyboard does not make connection and therefore will not turn on.

The double sided foam is easily handled with a few drops of heptane which is sold in craft stores as UN-DU adhesive remover.


#11

Randy - regarding the zebra connector, so it is actually designed to make contact purely by compression and I didn't damage it or break anything? That is very useful to know because it means I can take it apart again without any worry. Thanks very much for the info!

Mark


Quote:
That little blue/black piece is an elastomeric connector a.k.a. a "zebra". These are very common in modern electronics and are most often seen used to connect LCD's. They need to be in compression to work, the back of the calculator provides the pressure points so without the back in place and a screw in the upper right position, the keyboard does not make connection and therefore will not turn on.

The double sided foam is easily handled with a few drops of heptane which is sold in craft stores as UN-DU adhesive remover.


#12

Randy, isn't it also true that the "under LCD window" cleaning that is the subject of this thread is almost impossible to do with the later Voyagers, which have everything mounted on one PCB heat-staked to the top cover assembly?

I disassembled one of my HP-15C units that had what appeared to be a hairline crack in the corner of the LCD. I could see no way to easily access the under surface of the LCD window. Fortunately, the "crack" was truely hairline...it was only a fine hair that had found its way there. Still, it took the strongest vacuum machine I could find to pull it out.

Had anything else been between the LCD and the window, I suspect I'd have been SOL.


#13

Yes, beginning somewhere very late 1984 or early '85, the Voyager hardware packaging changed considerably.

Instead of the removable logic module built on a flexible film carrier, which was done to provide shock isolation for the LCD, everything was built on a single piece of FR4 that contained the keyboard, logic board and LCD as a single assembly.

I suspect this change was very close to or concurrent with the 41 changeover to the halfnut - which marked the first solidly mounted LCD design with a "unitized" keyboard/logic board/LCD combination in both product lines.

As a result, access to the LCD in both the later Voyagers and Halfnut 41's is only by removing the heat stake mushroom tops and pulling the complete board assembly out of the unit.

It the case of your 15C, you can carefully lift (pry) the logic board up a small bit to allow small bits of debris to come out with a vacuum. I would not recommend blasting canned air into the gap or around the LCD as one of the things that does happen is for the anti-reflective coating to start to peel away on the inside of the polycarbonate window. You really, really don't want that to happen.


#14

Thanks very much for the detailed information, Randy. Just by luck, as opposed to skill and knowledge, I had done exactly what you recommended and was successful.

On several websites I had seen some pictures of these later version PCBs removed from the Voyager case. I initially thought that was an indication that the PCB could be fairly easily removed from the case, only I couldn't figure out how. Now, I'm glad I didn't try the impossible.


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