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BitWiz · 02-23-2024, 11:34 PM

I recently acquired an JHP-71B (1BBB) that has had the 4 internal 4K memory chips replaced with 4 32K memory board. In addition the CPU has been sped up to 886KHz.

This is causing the MultiMOD to not work.

1. Are there any internal registers in the 71 that can slow down the bus so that the MultiMOD will work?

2. Short of removing the clock speed up, is there anyway to get the MultiMOD to work at this speed?

3. If there is no way to get the MultiMOD to work are there any other RAM/ROM emulators available for the 71B that are still in production?

I specifically would like to have the HP-41 Translator ROM and Forth/Assembler ROMs in my unit.

4. Does anyone have either these modules for sale or some kind of ROM emulation they are looking for a good home for.

And Last but not least the background of the LCD is spotted and dark. The LCD is fine and clear. Is there any way to clean that without moving all of the heat stakes and separating the keyboard board from the case front?

Pictures of the inside can be found here: https://www.facebook.com/photo/?fbid=937...1359683085

Thank you all,

Mike.

I am looking to buy/trade for (preferably at below ePay prices)

82161A Digital Cassette Drive
Any HP-IL Video Interface
9114B 3.5" Floppy Disk Drive
HP-IL Serial Interface
Any HP LED calculator
Any PDP-8 equipment, boards or peripherals

I am building 3D printed battery packs with fresh batteries for the Classic (82001), Woodstock (82019) and Topcat (82033) series machines. Please contact me directly if you are interested in purchasing any. Selling at below ePay prices. I also have a bunch of Mini Data Cassettes for sale or trade.

**rprosperi** · 02-24-2024, 01:13 AM

(02-23-2024 11:34 PM)BitWiz Wrote: [snip]

I specifically would like to have the HP-41 Translator ROM and Forth/Assembler ROMs in my unit.

[snip]

You cannot have both of these ROMs/Modules installed at the same time, as they both utilize a fixed-address ROM at E0000 (and they are not the same). The 41Trans ROM was derived from the original Forth/Assembler by Bill Wickes, and in the process he made many, many changes which resulted in the need to revise the RAM-based and both the soft- and hard-addressed ROM portions.

Although a technically impressive emulation of the 41, I've never met anyone who actually liked using it. It was created as a means for ISV/VAR developers to move their 41 programs onto the 71B quickly, while rewriting from scratch in BASIC (or assembler, or Forth, etc.), thus allowing their customers to move to the new, much faster machine with larger display, and better HP-IL support, right away and not have to wait for the re-write. And while some developers surely did this, very few of these ported programs, if any, ever saw the light of community users eyes (e.g. PPC, CHHU, etc.).

I'll email you about some of the items you're looking for.

BitWiz · 02-24-2024, 01:33 AM

(02-24-2024 01:13 AM)rprosperi Wrote:
(02-23-2024 11:34 PM)BitWiz Wrote: [snip]

I specifically would like to have the HP-41 Translator ROM and Forth/Assembler ROMs in my unit.

[snip]

You cannot have both of these ROMs/Modules installed at the same time, as they both utilize a fixed-address ROM at E0000 (and they are not the same). The 41Trans ROM was derived from the original Forth/Assembler by Bill Wickes, and in the process he made many, many changes which resulted in the need to revise the RAM-based and both the soft- and hard-addressed ROM portions.

Although a technically impressive emulation of the 41, I've never met anyone who actually liked using it. It was created as a means for ISV/VAR developers to move their 41 programs onto the 71B quickly, while rewriting from scratch in BASIC (or assembler, or Forth, etc.), thus allowing their customers to move to the new, much faster machine with larger display, and better HP-IL support, right away and not have to wait for the re-write. And while some developers surely did this, very few of these ported programs, if any, ever saw the light of community users eyes (e.g. PPC, CHHU, etc.).

I'll email you about some of the items you're looking for.

Bob,

I was under the impression that there were both 16K relocatable versions and 32k Fixed at 0xE000 versions. Isn't that the reason that is FORTH1B.DAT (16K) and HRDFTH_B.DAT (32K) as well as HP41TRANS.DAT (16K) and HP41TRANSHRD.DAT (32K)?

I look forward to hearing from you.

Mike

Sylvain Cote · (This post was last modified: 02-24-2024 03:54 AM by Sylvain Cote.)

Hello Mike,

(02-24-2024 01:33 AM)BitWiz Wrote: I was under the impression that there were both 16K relocatable versions and 32k Fixed at 0xE000 versions.

You are correct, if you try to install both module at the same time, both module will map itself to the same address (0xE0000) resulting in a bus lockup.
Which I can confirm because I just tried it. Wink

Code:

FORTHROM.BIN 16K relocatable

HRDFORTH.BIN 32K fixed at 0xE0000

FTH41ROM.BIN 16K relocatable

HRDFTH41.BIN 32K fixed at 0xE0000

Sylvain

edit: typo

BitWiz · 02-24-2024, 02:09 AM

(02-24-2024 02:03 AM)Sylvain Cote Wrote: Hello Mike,

(02-24-2024 01:33 AM)BitWiz Wrote: I was under the impression that there were both 16K relocatable versions and 32k Fixed at 0xE000 versions.
You are correct, if you try to install both module at the same time, both module will map itself to the same address (0xE0000) resulting in a bus lookup.
Which I can confirm because I just tried it.
Sylvain

I'm a tad bit confused. What is the point of having the 32K hard addressed image and the 16K image?

Sylvain Cote · (This post was last modified: 02-24-2024 02:29 AM by Sylvain Cote.)

(02-24-2024 02:09 AM)BitWiz Wrote: I'm a tad bit confused. What is the point of having the 32K hard addressed image and the 16K image?

FORTH is a low level language that was designed to over the hardware.
The 16K lex file mainly serve as a bridge between the BASIC system and the Forth system.

Excerpt from the Forth IMS

Quote:The functioning of FORTH in the HP-71 is based on absolute addresses.
The ROM dictionary is hard configured to always live at 0xE0000.
A problem arises when we examine the positioning of FORTH system variables and user definitions.
The entire RAM address space is managed by the BASIC O/S; this system works with entities called files.
The FORTH system had to respect the integrity of BASIC and therefore all FORTH system variables and user definitions have to exist within the franework of a file.
However, files move in RAM and, worse, their movement is unpredictable.
To solve these problems, FORTHRAM is always positioned at the beginning (lowest memory address) of the RAM file chain.
Directly beneath the beginning of file memory are the BASIC O/S configuration buffers (see the HP-71 IDS for a description of these buffers).
These buffers have a minimum and a maximum size.
Therefore it is possible to identify the lowest possible start address for a file in the file chain (2FA01) and the highest possible start address (2FAD3).
To this latter address we add 25 (hex) nibbles for file overhead (file name, time, creation date, etc.) plus 5 nibbles of storage for FORTH's purposes.
This gives us an address at which we can always count on being able to use for FORTH's variables, 2FAFD.
etc.

References:

**rprosperi** · 02-24-2024, 02:38 AM

It's almost as if I picked the exact right 90 minutes to do something else, eh? Thanks Sylvain.

The only way one can load both is with something like a FRAM71/FRAM71B, which lets you dynamically reconfigure (it's as if you physically R&R'd the modules) but this still means only one of them is available at any given time.

About 10 years ago, when FRAM71 was new, much exploring / experimenting /gnashing of teeth took place to try to fanagle these to work together, but it's just not going to work, the differences are too extreme. Even the fixed ROM-based words are not all at the same addresses, many (most?) of them differ, a result of the rather large changes BW had to make to make the 41Trans behave like a real 41.

mfleming · 02-24-2024, 03:38 AM

(02-24-2024 02:03 AM)Sylvain Cote Wrote: You are correct, if you try to install both module at the same time, both module will map itself to the same address (0xE0000) resulting in a bus lookup.
Which I can confirm because I just tried it.

Code:

FORTHROM.BIN 16K relocatable HRDFORTH.BIN 32K fixed at 0xE0000 FTH41ROM.BIN 16K relocatable HRDFTH41.BIN 32K fixed at 0xE0000

Sylvain

A MultiMod owner reported recently that a stock MultiMod and a Forth module in the same machine caused a lockup. He reported it as an error because he had disabled the MultiMod with a poke zero. Hey, how was I supposed to know that was a use case I should handle? Smile

[Cue the Marx Brothers clip about "Doctor, doctor, it hurts when I do this" ...]
~Mark
NB. Mike will get refund if no fix found.

BitWiz · 02-24-2024, 07:45 PM

The issue is my sped up 71B running at about 866Khz. This is too fast for the multimod. Here are my choices:

1. Find a way to switch the speedup on or off. My HP-41 has a 2.3X speed up that is switchable.
2. Replace the multimod with a device that can handle the speedup. Will the FRAM71 work at 866KHz?
3. Get real Forth and a Real 41 Translator modules and swap them manually as necessary
4. Remove the speedup. This is a last choice.

KimH · 02-24-2024, 08:09 PM

Depending on the CPU you have in your machine, you may get other issues with the speed-up - what is your serial number on the 71B? It could give a hint whether you have a cpu which can go as high as 1MHz - if not, there may be other issues you could encounter (and the choice might be to have 2 71B on hand as opposed to one.)

(02-24-2024 07:45 PM)BitWiz Wrote: The issue is my sped up 71B running at about 866Khz. This is too fast for the multimod. Here are my choices:

1. Find a way to switch the speedup on or off. My HP-41 has a 2.3X speed up that is switchable.
2. Replace the multimod with a device that can handle the speedup. Will the FRAM71 work at 866KHz?
3. Get real Forth and a Real 41 Translator modules and swap them manually as necessary
4. Remove the speedup. This is a last choice.

BitWiz · 02-24-2024, 08:24 PM

(02-24-2024 08:09 PM)KimH Wrote: Depending on the CPU you have in your machine, you may get other issues with the speed-up - what is your serial number on the 71B? It could give a hint whether you have a cpu which can go as high as 1MHz - if not, there may be other issues you could encounter (and the choice might be to have 2 71B on hand as opposed to one.)

The model I have is 1BBB with the single screw in the battery compartment. There is a picture of the insides https://www.facebook.com/photo/?fbid=937...1359683085

As for having two 71's, are you offering one of your "extra's" as the price that an unemployed engineer can afford Smile

Also, this 71 has 128K of internal memory in addition to being sped up.

And the HP-IL works with the speed up.

mfleming · 02-25-2024, 03:28 AM

(02-24-2024 07:45 PM)BitWiz Wrote: Will the FRAM71 work at 866KHz?

No, the FRAM71 manual explicitly excludes any machine with a fast clock mod.

Would be nice to see those pictures on someplace other than a Facebook closed garden. Smile

Sylvain Cote · 02-25-2024, 04:09 AM

(02-25-2024 03:28 AM)mfleming Wrote: Would be nice to see those pictures on someplace other than a Facebook closed garden.

Agreed! ... since I do not have an account on any social media, so I cannot see them.

BitWiz · 02-25-2024, 11:49 PM

(02-25-2024 04:09 AM)Sylvain Cote Wrote:
(02-25-2024 03:28 AM)mfleming Wrote: Would be nice to see those pictures on someplace other than a Facebook closed garden.
Agreed! ... since I do not have an account on any social media, so I cannot see them.

Here is a link to them on my google drive:

https://drive.google.com/drive/folders/1...drive_link

mfleming · 02-26-2024, 01:18 AM

I'm sure there's a writeup somewhere on how to modify the 71B clock for higher speed, given what Hans has written. Does the description include a means of switching from normal to turbo speed by toggling between L1 inductor values? (180 uH to 70 uH)

Pointer appreciated!
~Mark

J-F Garnier · 02-27-2024, 09:01 AM

(02-26-2024 01:18 AM)mfleming Wrote: I'm sure there's a writeup somewhere on how to modify the 71B clock for higher speed, given what Hans has written. Does the description include a means of switching from normal to turbo speed by toggling between L1 inductor values? (180 uH to 70 uH)

Pointer appreciated!
~Mark

I considered to do it some years ago on my 1LK7-based HP-71B but never did it (emu71 is MUCH faster anyway).
I was considering changing the caps but changing the inductor may be better.
So should I have to do it now, I may try to add a switchable 120uH in // with the original 180uH to get about 70uH.
I doubt a switchable turbo mode for the HP-71B has be done before but I may be wrong.

J-F

mfleming · 02-27-2024, 12:30 PM

I've seen several references to a switchable turbo mode for the 41C, but the only place I've seen reference to a faster 71B is the disclaimer in Han's FRAM71 user manual. The FRAM71 may handle a higher clock speed from Han's demonstration, but the MultiMod most definitely cannot. There is enough slack in timing to handle normal variation from unit to unit. A 50% bump in bus timing is just too much for the MultiMod to keep pace. The downside of software emulation... Sad

BitWiz · 02-27-2024, 05:34 PM

(02-27-2024 12:30 PM)mfleming Wrote: I've seen several references to a switchable turbo mode for the 41C, but the only place I've seen reference to a faster 71B is the disclaimer in Han's FRAM71 user manual. The FRAM71 may handle a higher clock speed from Han's demonstration, but the MultiMod most definitely cannot. There is enough slack in timing to handle normal variation from unit to unit. A 50% bump in bus timing is just too much for the MultiMod to keep pace. The downside of software emulation...

I had my HP-41CX Turbo'd (with a tiny switch in the charger compartment) to 2.3X back in the 80's. It still works!!