Date   

Re: Battery backup jumper for 1000 M-E-F machines

Mike Loewen
 

On Sat, 14 May 2022, Jack Rubin wrote:

I should know this but I've forgotten and haven't been able to find a reference. For 1000 M-E-F power supplies equipped with the battery backup option, there is a plug that goes into the BAT INPUT receptacle on the back of the power supply to enable operation. It contains a single resistor that goes across the outer inputs of the center row of the plug. Can anyone help me with value of the resistor (and correct me if I'm wrong about the plug positions to use)?
820 ohm.

Mike Loewen mloewen@...
Old Technology http://q7.neurotica.com/Oldtech/


Battery backup jumper for 1000 M-E-F machines

Jack Rubin
 

I should know this but I've forgotten and haven't been able to find a reference. For 1000 M-E-F power supplies equipped with the battery backup option, there is a plug that goes into the BAT INPUT receptacle on the back of the power supply to enable operation. It contains a single resistor that goes across the outer inputs of the center row of the plug. Can anyone help me with value of the resistor (and correct me if I'm wrong about the plug positions to use)?

Thanks -
--
Jack
www.computerarium.org


Re: 79xx drive emulator

al_kossow
 

On 5/14/22 1:02 PM, Glen Slick wrote:
Not surprised to see that one grabbed right away at a reasonable price.
I am
People do realize it expects to talk to and use MO media?


Re: 79xx drive emulator

Glen Slick
 

On Sat, May 14, 2022, 11:57 AM Mattis Lind <mattislind@...> wrote:

There is a drive emulator on Ebay (not mine). Emulates HP79XX drives. 

Perhaps of interest to someone. 


https://www.ebay.com/itm/275310974648


As far as I have seen those Arraid drive emulators rarely show up on eBay. Not surprised to see that one grabbed right away at a reasonable price.

The connector on the back of that one doesn't match the images in the datasheet:


What controller would connect to that?


Re: HP 9845A Power Supply Troubleshooting Help

 

Hi Stan,

 

Could be a ROM error?

Does it work on CRT?

What if you PRINT “X”   ?

 

Thanks,

Harold

 

From: VintHPcom@groups.io <VintHPcom@groups.io> On Behalf Of Stan
Sent: Saturday, May 14, 2022 7:05 PM
To: VintHPcom@groups.io
Subject: Re: [VintHPcom] HP 9845A Power Supply Troubleshooting Help

 

Hi Ansgar,

 

One more observation:

 

I wrote a simple BASIC program with a loop to print lines of “X”s of varying length, from 1 to 76 characters. When I ran the program, the paper advanced after each line printed, but what printed was still a one-pixel high line. The length of each line was either short (about 1”) for printed lines of 1 to 21 characters, or longer (about 2-1/2”) for lines of 26 to 76 characters. I’ve attached a photo.

 

Any ideas?

 

Thanks,

Stan


79xx drive emulator

Mattis Lind
 

There is a drive emulator on Ebay (not mine). Emulates HP79XX drives. 

Perhaps of interest to someone. 


https://www.ebay.com/itm/275310974648


Re: HP 9845A Power Supply Troubleshooting Help

Stan
 

Hi Ansgar,

 

One more observation:

 

I wrote a simple BASIC program with a loop to print lines of “X”s of varying length, from 1 to 76 characters. When I ran the program, the paper advanced after each line printed, but what printed was still a one-pixel high line. The length of each line was either short (about 1”) for printed lines of 1 to 21 characters, or longer (about 2-1/2”) for lines of 26 to 76 characters. I’ve attached a photo.

 

Any ideas?

 

Thanks,

Stan

_._,_._,_


Re: HP 9845A Power Supply Troubleshooting Help

Stan
 

Hi Ansgar,

 

Lots more progress yesterday!

 

After cleaning all of the contacts on all of the removable PC boards and ROMs with Deoxit Gold, I reassembled the 9845A and now it boots up fine and is (mostly) working. I can enter programs and run them just fine. The display has the famous “mold” so I will have to disassemble and fix that. Do you have any hints for doing that?

 

Also, the thermal printer has a strange problem. When I print a line, the printhead will fire, but the paper does not advance, so all the dots are printed in a row that is one pixel high. I can advance the paper with the paper advance button, so I can confirm that the paper advance motor is working. It seems that the printer either is not receiving, or is not responding to the signal from the control board to advance one pixel row when printing. Do you have any ideas about this problem?

 

I looked through all the manuals I have, but I can’t confirm if on power up that the default ”PRINTER IS” device is the display. I have to enter “PRINTER IS 0” to use the internal printer. Is this the correct behavior?

 

Thanks yet again,

Stan

From: VintHPcom@groups.io <VintHPcom@groups.io> On Behalf Of Ansgar
Sent: Wednesday, May 11, 2022 9:26 PM
To: VintHPcom@groups.io
Subject: Re: [VintHPcom] HP 9845A Power Supply Troubleshooting Help

 

The two beeps are a 'I'm alive' message from the PPU, which is responsible for the startup phase. The PPU also clears the screen and initiates the cursor. Then a memory check will start, where the PPU checks all memory blocks, starting with block 1. Normally the PPU will list ROM locations on the integrated thermo printer if they are bad. See https://hp9845.net/9845/tutorials/troubleshooting/#start_up for details. The test code is in ROM and also uses a portion of memory block 1 as scratch RAM. If that portion is bad, the test can hang up and nothing happens.

I assume that the nano processor on the printer controller board also does a quick self test, where it lits the LED for a short while after power-up, which would be normal behavior.

-Ansgar


HP 9000 300 series paint color

Manuel Maseda
 

Anyone have ideas about a good matching color to repaint a case?

Manuel


Re: Unknown HP21xx Board

Achim Buerger
 

Stephen,
thank you, but maybe there is a misunderstanding. I know the 12554 manual, but I could use a manual for the CAMSCO board. Maybe you have any notes of your findings regarding the jumper settings?

Achim


File /12554A_OperatingAndServiceManual_12554-90021_50pages_Aug69.pdf uploaded #file-notice

Group Notification <noreply@...>
 

The following files and folders have been uploaded to the Files area of the VintHPcom@groups.io group.

By: Stephen Hanselman <kc4sw.io@...>

Description:
12554 16 bit duplex register positive logic


Re: Unknown HP21xx Board

Stephen Hanselman
 

ooops, i uploaded the 12554 manual.  i've seen the board before and as i remember it took a little playing around with the switches to match the w1->w8 jumpers on the HP board.

steve, KC4SW


Re: Unknown HP21xx Board

Stephen Hanselman
 

i just uploaded the manual to the files location

Steve, KC4SW


Re: Unknown HP21xx Board

Achim Buerger
 

Update: I found out that the board is likely compatible to the HP12554. At least the corresponding diagnostic program runs without error. Also the cable edge connector matches to that of a 12554.
The only question is now, what is the meaning of the four dip switch arrays. I can only guess the function is similar to the jumpers on the 12554, but there is no obvious correspondence between these.
I would really appreciate if someone could share a manual. Otherwise I would have to reverse engineer the logic.


Re: 2x HP6400 + plenty of accessories for sale (Switzerland, Biel/Bienne) #VintageHPComputers

ChrisBeee
 

Hello OLi,
did you receive my e-mail? If not, please check your spam folder.
Cheers
Chris


Re: HP 9845A Power Supply Troubleshooting Help

Stan
 

Thanks for the clarification! Now I need to pull boards and clean contacts…

 

From: VintHPcom@groups.io <VintHPcom@groups.io> On Behalf Of Ansgar
Sent: Wednesday, May 11, 2022 9:26 PM
To: VintHPcom@groups.io
Subject: Re: [VintHPcom] HP 9845A Power Supply Troubleshooting Help

 

The two beeps are a 'I'm alive' message from the PPU, which is responsible for the startup phase. The PPU also clears the screen and initiates the cursor. Then a memory check will start, where the PPU checks all memory blocks, starting with block 1. Normally the PPU will list ROM locations on the integrated thermo printer if they are bad. See https://hp9845.net/9845/tutorials/troubleshooting/#start_up for details. The test code is in ROM and also uses a portion of memory block 1 as scratch RAM. If that portion is bad, the test can hang up and nothing happens.

I assume that the nano processor on the printer controller board also does a quick self test, where it lits the LED for a short while after power-up, which would be normal behavior.

-Ansgar


File Notifications #file-notice

Group Notification <noreply@...>
 

The following files and folders have been updated in the Files area of the VintHPcom@groups.io group.

By: Rik Bos <hp-fix@...>

Description:
HP 9826A configuration prom for the 09826-66516 boards in conjunction with Bootrom v3.X


The following files and folders have been uploaded to the Files area of the VintHPcom@groups.io group.

By: Rik Bos <hp-fix@...>

Description:
HP 9836U configuration PROM for use with the 09836-69513 68010 processor card.


Re: HP 9845A Power Supply Troubleshooting Help

Ansgar
 

The two beeps are a 'I'm alive' message from the PPU, which is responsible for the startup phase. The PPU also clears the screen and initiates the cursor. Then a memory check will start, where the PPU checks all memory blocks, starting with block 1. Normally the PPU will list ROM locations on the integrated thermo printer if they are bad. See https://hp9845.net/9845/tutorials/troubleshooting/#start_up for details. The test code is in ROM and also uses a portion of memory block 1 as scratch RAM. If that portion is bad, the test can hang up and nothing happens.

I assume that the nano processor on the printer controller board also does a quick self test, where it lits the LED for a short while after power-up, which would be normal behavior.

-Ansgar


Re: HP 2649A

John G. Australia
 

Hi Arnold, I am in Australia.

So shipping, etc, may be a problem.

But, let me know if nobody else is interested.

Thanks, John G.

On 2022-05-12 2:48 am, Arnold Lindberg wrote:
Hello ,
I have two HP2649A Terminals for sale,
One is in ok condition, and the other one have been forced open with
damage to the case and locking mechanism.
The damaged one had 8 boards inside, that have been removed.
So they are outside of the Terminal.
The better one have 6 boards inside and have never been opened,
neither one have been connected to mains power.
Links:
------
[1] https://groups.io/g/VintHPcom/message/8066
[2] https://groups.io/mt/91040296/429723
[3] https://groups.io/g/VintHPcom/post
[4] https://groups.io/g/VintHPcom/editsub/429723
[5] https://groups.io/g/VintHPcom/leave/832606/429723/1119633434/xyzzy


Re: HP 9845A Power Supply Troubleshooting Help

Stan
 

Hi Ansgar,

 

I've already recorded all of the PSU voltages and filed them with my troubleshooting and repair logs.

 

What is the significance of the two short beeps at startup? What is the function of the red LED on the printer driver circuit board?

 

My 9845A is configured with a full set of additional RAM cards. I assume I can remove all of them to help isolate the startup issue.

 

Is anything supposed to be shown on the display when the 9845A is booting up?

 

Thanks,

Stan

 

 

-----Original Message-----
From: <VintHPcom@groups.io>
Sent: May 11, 2022 2:21 PM
To: <VintHPcom@groups.io>
Subject: Re: [VintHPcom] HP 9845A Power Supply Troubleshooting Help

 

Well, this is quite good news. You should take the opportunity to check the voltages at the PSU in any case (can be advantagous for later troubleshooting).

So the system starts into the boot process, but hangs during boot (the blinking is a feature of the display, and independent of any CPU activity).

There are two main causes for this, one is erroneous RAM access in the lower address range (so that power-on diagnostics cannot start) or faults in the plugin ROMs.

I would first of all suggest to clean to contacts of both the RAM boards and the ROM plugin modules with isopropyl alcohol, and then try again.

If the problem persists, try to swap the address configuration of the RAM boards (I am not sure but I think you can configure their address space, see the 9845A service manual). Defects in the ROM plugin modules are less likely.

-Ansgar


 

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