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HP41 CL Board installation
11-11-2017, 09:37 PM (This post was last modified: 11-11-2017 09:40 PM by Neve.)
Post: #1
HP41 CL Board installation
Hi,

I received my V5 board. Everything is fine and works. Thanks Monte.

I just have question not specifically related to this board itself or to the update process in particular, but rather regarding the serial connector.
For mechanical reasons which are not relevant, I had to desolder the 2.5 jack to install it. I took a picture of the wires before I did. But as it turns out, the picture is blurry.
Can anyone tell me where the wires need to be connected? I can’t see anything... Ooops.
Also, the wires press outward on the spacer between the 2 halves. Hmmmm.

FYI, I have an older Tallkey version with nuts holding down the board. I removed them and screwed them back on very easily.

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11-11-2017, 09:51 PM
Post: #2
RE: HP41 CL Board installation
Pages 91-93 in: http://systemyde.com/pdf/sy41cl.pdf explain the connections
better than I can in words.
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11-11-2017, 10:18 PM
Post: #3
RE: HP41 CL Board installation
(11-11-2017 09:51 PM)Monte Dalrymple Wrote:  Pages 91-93 in: http://systemyde.com/pdf/sy41cl.pdf explain the connections
better than I can in words.

Thanks.

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11-13-2017, 05:51 PM
Post: #4
RE: HP41 CL Board installation
In case anyone comes looking here for others' experiences installing the V5 board, I can report that it was pretty easy. I'd never opened a 41 before and Monte's instructions were very clear. I had the "not really reusable" connector between the CPU board and main board but I decided to try to reuse it anyway. It took about 20 minutes of very gentle prodding and pulling but I managed to separate the CPU board from the connector without damaging it. During reassembly, definitely follow the advice to squeeze the two halves of the case together while tightening the screws. This makes it easy to tell when the screws are in all the way so you don't over-tighten.

My only suggestion is that the "tools you'll need" paragraph on page 9 might mention double-stick tape if you're installing the serial port.
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11-13-2017, 06:18 PM
Post: #5
RE: HP41 CL Board installation
Is there a history with the difference between V1, 2, 3, 4 and 5 boards?
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11-13-2017, 06:30 PM
Post: #6
RE: HP41 CL Board installation
(11-13-2017 06:18 PM)HP-Collection Wrote:  Is there a history with the difference between V1, 2, 3, 4 and 5 boards?

Sylvain's CL Auto-Update HHC 2017 presentation includes details of the variations between the board generations, dates they were sold, number sold by country, etc. About all the info you might want about the CL boards.

--Bob Prosperi
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11-13-2017, 06:37 PM
Post: #7
RE: HP41 CL Board installation
(11-13-2017 06:30 PM)rprosperi Wrote:  
(11-13-2017 06:18 PM)HP-Collection Wrote:  Is there a history with the difference between V1, 2, 3, 4 and 5 boards?

Sylvain's CL Auto-Update HHC 2017 presentation includes details of the variations between the board generations, dates they were sold, number sold by country, etc. About all the info you might want about the CL boards.

A link???

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11-13-2017, 07:54 PM
Post: #8
RE: HP41 CL Board installation
(11-13-2017 06:37 PM)Neve Wrote:  
(11-13-2017 06:30 PM)rprosperi Wrote:  Sylvain's CL Auto-Update HHC 2017 presentation includes details of the variations between the board generations, dates they were sold, number sold by country, etc. About all the info you might want about the CL boards.

A link???
See the .. Sylvain
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11-15-2017, 08:07 AM
Post: #9
RE: HP41 CL Board installation
I got my V5 board last week

The 41C I wanted to install it into was an older machine (S/N 2036A01297), which has 2 metal nuts holding down the motherboard onto the display/keyboard PCB (see picture). The metal nuts screw directly onto the plastic screw posts - needless to say the thread on the plastic posts is easily damaged.

That is what happened to me. When I screwed the nuts back to hold the 41CL board, they did not press it enough to make contact with the display/keyboard PCB, and I could not get the 41CL to work.

Luckily, I live a few miles from Monte, and he identified the problem. The solution was to use the calculator back of a newer HP-41CV (S/N 2201S41038) which I had. For such newer models, there are no nuts to hold the motherboard - the calculator back has some plastic cups that press the motherboard down

In conclusion: if you have an older HP-41C with the metal nuts, be very careful when you remove the nuts and screw them back. For the later models without the nuts, the installation is quite straightforward

I will need to re-assemble my leftover 41C-41CV hybrid. My objective is to create the little cuts that press the motherboard down - probably glueing a few nylon washers together and onto the calculator back. Will post procedure once (if) validated

Gene pointed out at the last HHC that installing a 41CL board may be scary, but it is actually very straightforward. And the result is an unbelievable machine...


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11-15-2017, 08:24 AM
Post: #10
RE: HP41 CL Board installation
(11-15-2017 08:07 AM)Benoit Maag Wrote:  I got my V5 board last week

The 41C I wanted to install it into was an older machine (S/N 2036A01297), which has 2 metal nuts holding down the motherboard onto the display/keyboard PCB (see picture). The metal nuts screw directly onto the plastic screw posts - needless to say the thread on the plastic posts is easily damaged.

That is what happened to me. When I screwed the nuts back to hold the 41CL board, they did not press it enough to make contact with the display/keyboard PCB, and I could not get the 41CL to work.

And the result is an unbelievable machine...

Mine is serial #2027A00688, and the nuts screwed back on perfectly without any damage to the threads. The only problem I encountered was that the previous owner had lightly glued the battery connector to the front case. I guess I could somehow remove it, but I’m afraid to damage it. The two sides lift up a bit, but the middle is quite stuck.
So my problem was that I plugged the serial connector to the board first. Then I realized I couldn’t push it to the front because the battery connector was it the way and couldn’t be removed. So I had to desolder the wires from the plug. Also there is still a little bulge on the side where the wire are running along the case (I forgot the double tape). That might solve this issue...
Other than that, everything is perfect. Although I may finally fit the V5 board onto another machine and sell this one, because the display contrast is lower than my other Fullnut CX model. There is really a big difference, which is particularly annoying in low light conditions. So I haven’t put the CL sticker on yet until I decide to get a CV or a later model (non-tallkey) 41C with better screen contrast.

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11-15-2017, 09:16 AM
Post: #11
RE: HP41 CL Board installation
(11-15-2017 08:24 AM)Neve Wrote:  
(11-15-2017 08:07 AM)Benoit Maag Wrote:  I got my V5 board last week

The 41C I wanted to install it into was an older machine (S/N 2036A01297), which has 2 metal nuts holding down the motherboard onto the display/keyboard PCB (see picture). The metal nuts screw directly onto the plastic screw posts - needless to say the thread on the plastic posts is easily damaged.

Mine is serial #2027A00688, and the nuts screwed back on perfectly without any damage to the threads.

Ditto for my 2034A009xx.

Greetings,
    Massimo

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11-27-2017, 03:47 AM
Post: #12
RE: HP41 CL Board installation
See below a description of how to hold the motherboard without nuts
The idea is a system similar to the little cups found in later HP-41C models

I used two nylon flange bearings (Hillman NFB-1025U H# 415599) bought at a major home improvement store. It was necessary to shorten them to about 2.5 mm thickness (rough cut with electrical wire cutting pliers, finish with sandpaper)

That's it - see attached pictures


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