HP-41 82161A HP-IL Tape Reader - Doesn't work anymore - Help Needed

[albertofenini]

Hi everyone,

We have been able to use, somehow, our tape reader.
We have three tapes, two of which (seen in the picture) have some mechanical problems

The first when loaded and accessed by
the XEQ DIR command gives the following error message DRIVE ERR but sometimes works
and produces a listing (not the one attached)

The second when loaded and accessed by
the XEQ DIR command gives always the following error messages DRIVE ERR or TRANSMIT ERR

Do you think this could be due to the small white cushion not correctly positioned ?

The third one which is labelled HP41 DEMO works and produces the listing attached.

How can we try to load one of the subroutines and see if it works ?
Does any of these demo programs are familiar for someone of you ?

thank you very much !!

   
   

[AndiGer]

Just these days I discovered Tony Duell's data cassette repair guide ....
https://www.hpmuseum.org/guest/duell/rep82176.pdf
HTH

[Dave Frederickson]

(04-13-2019 09:01 PM)albertofenini Wrote:  The second when loaded and accessed by
the XEQ DIR command gives always the following error messages DRIVE ERR or TRANSMIT ERR

Do you think this could be due to the small white cushion not correctly positioned ?

Yes. The pads on both tapes in the attached pic are defective.

Note that is is only necessary to fix one pressure pad. Since the goal is to recover the data from the tapes, once the data has been recovered the tape essentially serves no purpose and the one repaired spring/pressure pad can be used on subsequent tapes.

Since virtually all tapes are unreliable due to age, the tape drive only serves the purpose of recovering data from old tapes. Once the data has been copied to a LIF disc image the PIL-Box is the preferred method for accessing the data.

Dave

[albertofenini]

Thanks everyone for the help, but we have a bigger problem ... which is why we changed the title of the post

We wanted t try to read a program from the demo tape and we discovered that the Tape Reader
does not turn on anymore.

Doesn't with only the battery, doesn't with the battery and the charger,
but without battery and with the charger when we move the switch to the ON position just the BATT led turns on
but nothing more (hope we didn't fried anything by doing this)

Obviously we have tested the charger, the battery, tried different ones and the problem is not there

So we opened the unit and we found the switch traces very dirty (see pic)
We cleaned them as they were kind on joint together, so we separated with the tip of the exacto as these should be.

However, when we connected the unit together, nothing, it still does not work.

We don't have the schematics for this unit, I have checked on the Schematics site,
but I have only found those for the HP-IL Printer, I'm wondering if the PSU is similar.

Also, we have found on the bench a strange small button (pictured with a rubber so that you can see proportions), that we don't think is coming from the unit, but you never know.

Has anyone have experienced a problem like this and tried to repair the Tape reader ?
Thanks for help !!!!

P.S. we have noted that the upper left corner and the bottom left corner of the switch traces are
like connected, with a very low resistance (6 ohm) which may be correct since
there is actually a big resistor of 5.6 ohm the connects that two but we don't know if it is ok

   
   
   
   
   

[Dave Frederickson]

Here's the Service Manual.

http://www.hpmuseum.net/document.php?hwfile=2835

[albertofenini]

Thank you very much !!
I think this may be beyond our capabilities
Has anyone ever repaired a unit like this and while we go thru the manual
can gives a few hints on where to check ?
What I do you think of the power switch traces ?
Are now ok ??
Thanks a lot

[Dave Frederickson]

(04-14-2019 04:40 PM)albertofenini Wrote:  What I do you think of the power switch traces ?

The traces look okay. Don't forget to lubricate the switch with a dielectric grease, or even better, Lubriplate DS-ES.

Dave

[albertofenini]

Do you think it is normal that upper left and lowest left are almost connected ?
We looked at the manual but it is difficult to understand the position of the components
Is there any testing point like in some of the calculators we have repaired in the past ?

Since it was working as of lunch time today and it doesn’t turn even on I think it has to be something macroscopic related to power supply that’s why I’m interested in understanding where the voltages should be available and how much the values should be

[Dave Frederickson]

(04-14-2019 04:57 PM)albertofenini Wrote:  Do you think it is normal that upper left and lowest left are almost connected ?
We looked at the manual but it is difficult to understand the position of the components
Is there any testing point like in some of the calculators we have repaired in the past ?

Since it was working as of lunch time today and it doesn’t turn even on I think it has to be something macroscopic related to power supply that’s why I’m interested in understanding where the voltages should be available and how much the values should be

I'm not sure which contacts you're referring to. The schematic does show a 5.6 ohm resistor connected between two of the contacts (R1).

I suggest you start with the troubleshooting procedure in Table 4-4, Improper Turn-On.

Dave

[AndiGer]

Concerning the small button ...
Maybe it is from the battery connector of a Woodstock?
Just cleaned obe so came to my mind as I saw it now

[albertofenini]

(04-26-2019 03:16 AM)AndiGer Wrote:  Concerning the small button ...
Maybe it is from the battery connector of a Woodstock?
Just cleaned obe so came to my mind as I saw it now

Thanks for the hint but it is not, it is actually smaller and thinner and curved
looks like a miniature dome for the HP41 keyboard, but it is a 1/4 or less than that size
may as well have nothing to do with the reader and belong to something else ...

[albertofenini]

(04-14-2019 05:17 PM)Dave Frederickson Wrote:  I'm not sure which contacts you're referring to. The schematic does show a 5.6 ohm resistor connected between two of the contacts (R1).

I suggest you start with the troubleshooting procedure in Table 4-4, Improper Turn-On.

Dave

Hi Dave, hi Everyone, we started some troubleshooting this morning and this is what we have found out so far.

The test situation is this :
- AC charger connected
- A charged battery in place
- No tape inside the units
- No HP-IL connection to the HP-41 calculator
- Logic PCA and Drive PCA connected together

Table 4-4

We turned the switch ON even if it is not specified in the manual
step 1: measure voltage at the left side of W1 value is 1,6 (exptected 4.9 -5.1)
Manual suggests to go to table 4-11 Power Supply Circuit

Before we moved to table 4-11 we also took the other steps described in table 4-4 and these are the values :

step 2: measure A1U2-8, the value was 1,6 (expected 4.9 to 5.1)
step 3: measure A1DS3 anode, the value was 1,6 (expected 4.9 to 5.1)
step 4: measure A1U2-9 the value was 5,27 (expected 4.7 to 4.8)
step 5: measure A1U2-14 the value was 5,26 (expected 0 to 0,5)
step 6: measure A1Ds3 chathode, the value was 5,25 (exptected less than 3,2)

Is it correct that looking at these values the action suggested is to replace A1U2 and then A1U7 ?
Or it is more wise after step1 jump to table 4-11 ?

Table 4-11

step 1 : Turned the switch on
step 2 measure A1U2-4 and it was 1,6 (should be 4.9 to 5.1)
measure A1U2-8 and it was 1,6 (should be 4.9 to 5.1)

At this point the manual does not give a clear indication of what to do if BOTH values are out of range,
it says what to do if pin 4 is in the range and pin 8 is not in the range but not if both are out of range.

Nevertheless we proceded as described in the manual and we de-soldered left side of A1W1

Something weird started to happen, the left motor (the left one looking at the drive board from the trace side,
in working position that would be the right motor, the one that make the tape advance) started to run.
We left however the two PCA connected and we proceeded as follow

Step 4 : measure A1U2-4 and the value was 5.076 which is in range (expteced 4.9 to 5.1)

Following the manual we separeted the logic PCA from the drive PCA we reconnected W1 but the values
measured before remained all wrong, which for the manual means that the problem is on the logic PCA

We disconnected again W1, reconnected the two logic boards, left the motor run and took the following steps :

Step 5 : measure A1U7-7 and was 6V (expected 16 to 19)
Step 6 : measure A1U2-5 5.2 (expected 4.9 to 5.2)
Step 7 : measure A1U2-2 was almost 0V

However, then in the action it says often if 5V supply is above range... or if 5V supply is below range
How can we exactly find out if 5V supply is above or below range ?

thanks everyone for the support !!!

[Artur - Brasil]

Hi,

Have you really tested the batteries? You need to measure them when you turn on the drive. It drains a lot o current and Ni-Cd with no decent charging circuit is a real problem (the drive puts the large resistor beteween charger (and rectifying circuit) and batteries or nothing at all (on position) - such minimalist procedure kills battery vey fast and puts all drive under very high risk of getting too hot.
If voltage in batteries go down so much when turning on the drive, it will not work at all.
Let me know, ok?
As I did recently to my 41CX (put a celular phone battery and a decent charger circuit in it) I'm working on a larger batteries to my cassete drive, a larger step-up circuit and a charger. Even these larger and good batteries nad step-up circuit are having difficulties on supporting the turn on moments.