CMT 64Kb RAM module for HP-71b question
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09-08-2021, 01:23 AM
Post: #1
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CMT 64Kb RAM module for HP-71b question
I have recently received one of these, and it has this silver rectangle pouch(?) that fits mostly into the module as it is inserted into 71. Since I can’t find any instructions, etc. can someone let me know what that is, why is is different from the 32k modules? Thanks!
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09-08-2021, 02:51 AM
Post: #2
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RE: CMT 64Kb RAM module for HP-71b question
It is a backup battery.
When setup as an IRAM, the CMT 64KB RAM module with the inserted battery can be used to move data between 71B's or as an external backup as long as the battery is working. As specified in the manual, the battery must be inserted correctly in the module, otherwise it may damage it. Sylvain |
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09-08-2021, 02:56 AM
(This post was last modified: 09-08-2021 02:57 AM by rprosperi.)
Post: #3
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RE: CMT 64Kb RAM module for HP-71b question
(09-08-2021 01:23 AM)polbit Wrote: I have recently received one of these, and it has this silver rectangle pouch(?) that fits mostly into the module as it is inserted into 71. Since I can’t find any instructions, etc. can someone let me know what that is, why is is different from the 32k modules? Thanks! That's a battery. The 32K modules could preserve contents for a few seconds, e.g. while swapping ports; the board/component design had enough capacitance (maybe not the right term here) to maintain the RAM contents. But the 64K+ modules could not retain their contents, so CMT added this very small lithium battery, to similarly retain RAM contents for short periods. Your battery is almost certainly dead, and unfortunately, no one has been able to locate a supplier for replacement batteries. The module itself will still work fine, even with a dead battery, but if you remove it from a 71B, it will instantly lose contents. Yeah, he beat me... --Bob Prosperi |
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09-08-2021, 11:44 AM
Post: #4
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RE: CMT 64Kb RAM module for HP-71b question
Thanks! I figured it was a dead battery, just an unusual shape
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10-09-2021, 10:30 AM
Post: #5
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RE: CMT 64Kb RAM module for HP-71b question
I finally had a chance to actually use the module, and unfortunately all is not well - at first when used as main RAM, the 71b would crash after entering a program and running it for a bit, but MEM would show full amount. Now when I plug it and reset the calc, it’s showing 16K less, and no longer causes crashes. When and free the 1st port, then claim it again, it then shows full memory. Proceeding to free the port again causes it to crash…
Does anybody repair these by any chance? Or is there anything I can try myself? |
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10-09-2021, 09:10 PM
(This post was last modified: 10-09-2021 09:16 PM by Dave Frederickson.)
Post: #6
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RE: CMT 64Kb RAM module for HP-71b question
(10-09-2021 10:30 AM)polbit Wrote: Does anybody repair these by any chance? Or is there anything I can try myself? Trim a business card to the width of the module opening. Moisten about 1/4" of the end of the card with DeoxIT D-Series. Insert and remove the card into the module a bunch of times. If it's a contact problem hopefully this will take care of it. Does the problem occur with all ports? Dave |
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10-09-2021, 10:52 PM
Post: #7
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RE: CMT 64Kb RAM module for HP-71b question
(10-09-2021 09:10 PM)Dave Frederickson Wrote:(10-09-2021 10:30 AM)polbit Wrote: Does anybody repair these by any chance? Or is there anything I can try myself? Thanks Dave, I will definitely try that. Yes, I tried three ports on two different 71b machines. |
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10-09-2021, 11:43 PM
Post: #8
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RE: CMT 64Kb RAM module for HP-71b question
(10-09-2021 09:10 PM)Dave Frederickson Wrote: Trim a business card to the width of the module opening. Moisten about 1/4" of the end of the card with DeoxIT D-Series. Insert and remove the card into the module a bunch of times. If it's a contact problem hopefully this will take care of it. Well, I cleaned it, but it didn't seem to help. However, I realized that I have always tested with MultiMod (default config). Removed it and everything works perfectly. Furthermore, trying three 32K RAM modules with MultiRom installed the third one always has issues, just like the behavior of the second port of my 64K module when I had it installed with one 32K module. When I'm only using 2x32K or 1x64K, MultiRom works fine... Looks like false alarm on the RAM. |
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10-10-2021, 01:02 AM
Post: #9
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RE: CMT 64Kb RAM module for HP-71b question
(10-09-2021 11:43 PM)polbit Wrote:(10-09-2021 09:10 PM)Dave Frederickson Wrote: Trim a business card to the width of the module opening. Moisten about 1/4" of the end of the card with DeoxIT D-Series. Insert and remove the card into the module a bunch of times. If it's a contact problem hopefully this will take care of it. I always run Paul Berger's MEMBUF, available in the FRAM71 Toolkit, to verify memory configuration. |
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10-10-2021, 12:07 PM
Post: #10
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RE: CMT 64Kb RAM module for HP-71b question
Yes, you've run out of address space with the default MultiMod configuration plus three 32K RAM modules. I think the address assignment after power up would be
E0000 Forth hard ROM C0000 32K RAM A0000 32K RAM 80000 32K RAM 60000 32K Math ROM 40000 32K JPC ROM (from first configuration pass) 40000 16K Forth ROM 40000 16K ULIB (from first configuration pass) I'm not quite sure how the MultiMod would respond in this setting. Wish I had the RAM to reproduce the problem Try running the suggested utility to see what you get. Remember kids, "In a democracy, you get the government you deserve." |
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10-10-2021, 05:40 PM
(This post was last modified: 10-10-2021 06:19 PM by Sylvain Cote.)
Post: #11
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RE: CMT 64Kb RAM module for HP-71b question
(10-10-2021 12:07 PM)mfleming Wrote: Yes, you've run out of address space with the default MultiMod configuration plus three 32K RAM modules. I think the address assignment after power up would beSure ? VER$ -> HP71:1BBBB RCPY:E FTH:1B EDT:A KBD:C STRU:A MATH:2B JPC:F05 HPIL:1B Modified MEMBUF output for MULTIMOD default config no additional memory module Code: Addr. Range Port Dev Seq Size Addr Type Description Code: 38000..3FFFF Unused 16K Code: 90000..9FFFF Unused 32K Modified MEMBUF output for MULTIMOD default config with three 32K RAM Code: Addr. Range Port Dev Seq Size Addr Type Description Code: 38000..3FFFF Unused 16K Code: 90000..9FFFF 5 2 0 32 90000 2 JPC ROM 32K Modified MEMBUF output for MULTIMOD default config with four 32K RAM (48K Unused) Code: Addr. Range Port Dev Seq Size Addr Type Code: 70000..71FFF 0 0 0 4 70000 0 Internal RAM 4K Code: 90000..9FFFF Unused 32K Modified MEMBUF output for MULTIMOD default config with two 32K RAM and two 64K RAM Code: Addr. Range Port Dev Seq Size Addr Type Code: 70000..7FFFF 4 0 0 32 70000 0 External RAM 32K Port 4.00 first 32K of 64K Module Code: A0000..A7FFF 0 5 0 16 A0000 2 HP-IL ROM 16K |
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10-10-2021, 08:33 PM
Post: #12
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RE: CMT 64Kb RAM module for HP-71b question
Ah, you're right. I was a power of two off on module address space occupancy. I don't see ULIB52 in the version list or MEMBUF listing. Could you poke a "3" to enable it? I also haven't seen the HP-IL ROM at 40000 before either. Looks like I'll have to hook up my PIL-Box and load MEMBUF myself!
The OP's description of a crash after a few minutes of operation implies to me that there is an address range overlap between two devices, both of which want to drive the data bus on a read. I take it you're not seeing that... Remember kids, "In a democracy, you get the government you deserve." |
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10-11-2021, 12:32 AM
(This post was last modified: 10-11-2021 12:42 AM by Sylvain Cote.)
Post: #13
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RE: CMT 64Kb RAM module for HP-71b question
(10-10-2021 08:33 PM)mfleming Wrote: Ah, you're right. I was a power of two off on module address space occupancy. I don't see ULIB52 in the version list or MEMBUF listing. Could you poke a "3" to enable it? I also haven't seen the HP-IL ROM at 40000 before either. Looks like I'll have to hook up my PIL-Box and load MEMBUF myself! MULTIMOD Code: POKE "2C000","3" VER$ Code: HP71:1BBBB RCPY:E FTH:1B EDT:A KBD:C STRU:A MATH:2B JPC:F05 HPIL:1B ULIB:c RUN MEMBUF (MULTIMOD only) Code: Port Dev Seq Size Addr Type Description Code: 0 5 0 16 40000 2 HP-IL 16K ROM RUN MEMBUF (MULTIMOD only + 2x 32K RAM) Code: Port Dev Seq Size Addr Type Description Code: 0 5 0 16 60000 2 HP-IL 16K ROM RUN MEMBUF (MULTIMOD only + 3x 32K RAM) Code: Port Dev Seq Size Addr Type Description Code: 0 5 0 16 70000 2 HP-IL 16K ROM (10-10-2021 08:33 PM)mfleming Wrote: The OP's description of a crash after a few minutes of operation implies to me that there is an address range overlap between two devices, both of which want to drive the data bus on a read. I take it you're not seeing that...I am not experiencing any crash on my side with or without ULIB activated |
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10-11-2021, 03:06 AM
(This post was last modified: 10-11-2021 03:14 AM by polbit.)
Post: #14
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RE: CMT 64Kb RAM module for HP-71b question
After spending some time testing on 1BBBB and 2CDCC 71 machines, and moving my RAM modules around, here is my conclusion:
- MultiRom with ulib52 enabled, with HP-IL works with 2x32K/1x64K RAM. Adding 3rd 32K RAM makes it crash as soon as I free port of the 3rd RAM module, or randomly while in use. - if I disable ulib52 OR remove HP-IL module, I can reliably use the 3rd RAM module. EDIT: I’ll load MEMBUF tomorrow to get some output and share, didn’t have my Pil-Box with me… |
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10-11-2021, 03:38 AM
Post: #15
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RE: CMT 64Kb RAM module for HP-71b question
(10-11-2021 03:06 AM)polbit Wrote: After spending some time testing on 1BBBB and 2CDCC 71 machines, and moving my RAM modules around, here is my conclusion: Consider that initially the 3rd RAM module is configured as RAM, but when you freeport it it's configured as ROM/IRAM. See https://www.hpmuseum.org/forum/thread-76...l#pid67770 thru Post #23. |
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10-11-2021, 06:50 AM
Post: #16
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RE: CMT 64Kb RAM module for HP-71b question
(10-11-2021 12:32 AM)Sylvain Cote Wrote: MULTIMOD Did you deliberately set PORT (0.00) to IRAM? If yes, you may not be in the same configuration as the OP. If not, it may be the sign of something wrong. J-F |
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10-11-2021, 11:31 AM
(This post was last modified: 10-11-2021 11:47 AM by polbit.)
Post: #17
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RE: CMT 64Kb RAM module for HP-71b question
Here is my output:
Working configuration: VER$ Code: HP71:1BBBB FTH:1B EDT:A KBD:C STRU:A MATH:2B JPC:F05 HPIL:1B MEMBUF - 64K in port 1, 32K in port 2 Code: Port Dev Seq Size Addr Type Code: 2 0 0 32 50000 0 Non-working configuration: VER$ Code: HP71:1BBBB FTH:1B EDT:A KBD:C STRU:A MATH:2B JPC:F05 HPIL:1B ULIB:c MEMBUF - 64K in port 1, 32K in port 2 Code: Port Dev Seq Size Addr Type Code: 2 0 0 32 50000 0 And after FREE PORT(2) and Memory Lost: Code: Port Dev Seq Size Addr Type Code: 0 5 0 16 60000 2 |
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10-11-2021, 12:44 PM
(This post was last modified: 10-11-2021 12:47 PM by Sylvain Cote.)
Post: #18
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RE: CMT 64Kb RAM module for HP-71b question
(10-11-2021 06:50 AM)J-F Garnier Wrote: Did you deliberately set PORT (0.00) to IRAM?Yes, I was tired of reloading MEMBUF, but you are right I should not have done this. I have redone the tests and there is a problem. When I do polbit configuration with a 32KB RAM module in port 1, 2, and 3, it seems to work, but when I free one on the 32KB RAM port, I get a Memory Lost on the first free port but not on the others. Startup configuration Code: INIT 3 → "Memory Lost" , lets start clean First free first port: Code: FREE PORT(1) → "Memory Lost" , what? not expected Free second port: Code: FREE PORT(2) → works without loosing memory Get back first port: Code: CLAIM PORT(1) → works without loosing memory Get back second port: Code: CLAIM PORT(2) → works without loosing memory All modules are back to main memory, lets try to free a port again Free third port: Code: FREE PORT(3) → "Memory Lost", not expected but same behavior as last time Same behavior applies to any port, when all memory modules are part of main RAM, when I free a module I get a memory lost on the first FREE PORT but not on the others. I also did this test:
OK, how this is mapped ... Code: MEM → 98654 Power cycle and show memory map again Code: MEM → 146306 , memory is now what was expected mmm, ok, what happen when I remove module now ?
I have to go, but more test are needed on this last part. Sylvain |
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10-11-2021, 01:33 PM
(This post was last modified: 10-11-2021 01:36 PM by J-F Garnier.)
Post: #19
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RE: CMT 64Kb RAM module for HP-71b question
(10-11-2021 12:44 PM)Sylvain Cote Wrote: I also did this test: Interesting, all the internal 4K ports were put as IRAM. Then a power cycle restored them as MAIN RAM. Some background: during system config, each RAM (but not the ROM) is temporarily configured at 80000 to check if it is MAIN RAM or IRAM, by checking the IRAM signature, then parked at 40000 waiting for the final config. Maybe something is wrong there. J-F |
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10-11-2021, 02:55 PM
(This post was last modified: 10-11-2021 03:16 PM by Dave Frederickson.)
Post: #20
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RE: CMT 64Kb RAM module for HP-71b question
(10-11-2021 12:44 PM)Sylvain Cote Wrote: mmm, ok, what happen when I remove module now ? You MUST FREEPORT a RAM module before removing it. |
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