The 2005 Repair Diaries
The current visit diaries are now entered here, in reverse chronological
order, so the latest news is on top. ( more updates as and when we visit. Do check back
for pictures, updates and news on this project )
50th Episode:- 05/10/05
Work continued on the interface, trying to link an Apple Mac Laptop to the interface, but no joy.
Well some you win and some you dont. Hey this my 50th trip,
in three years work here, it
must be time to review what we are doing and the general direction of this project, we are
about 65 percent through at this point and Winter is fast approaching. Time to stand back and
do a long review of progress to date !
So we will be in touch with all of our supporters, and post an end of year Summary soon. 2006
will be a different year for this project ( one way or the other ) .
Just to prove flossie has her own view, at end of play this day we had to do a basic fix when
after running all day the machine started corrupting the Control registers. A G1 package in
5B17 had gone duff, so one more vintage PCB joins the list of parts we offer to our supporters.
49th Episode:- 07/09/05
Time to work on the tape punch again, this time we found that some of the problems were still
bad tracking and shorts on the board. We are winning, but very slowly on this item.
Big new item ! = We have built an interface to connect a PC ( laptop ) to the I/O connector.
We seem to be able to send one 4 bit digit of data under PC control ( out of little acorns )
Add-hoc redesign for Roger means we were able to extend this to 8 bits.
48th Episode:- 24/08/05
We have recieved a delivery of blank paper tape and teletype rolls, so first job today
is to replace the Paper Tape Punch interface driver card. This is a non standard
part of the project, as a Paper Tape Punch on a 1301 was a seperate device, but this unit is
an ad-hoc extension to the Paper Tape Reader Station.
It drives a teletype 100 char pert sec punch via some A28 ( 1301 standard ) cards and a
prototype board made with Vero board and Vero wire. Unfortunatly in episode 39 we started to
suffer from power supply problems in the paper tape station, the result was a damaged board.
Although rebuilt this board is proving very unreliable ( after all it is only a prototype )
The edge connections and pcb copnnectors are very poor and the vero wiring is now brittle with
age and keeps breaking. If we cannot resolve this problem the only sensible action is to stop
putting time, effort and money into rebuilding this board and make another with a good quality
edge connector and real wire.
Thank god the effort put into resolving the Paper Tape Reader Power Supply problems has paid
off in the form of a working paper tape reader !
It was proposed after episode 47 that we utilised the reader head connections to the second
channel, to stream data into the machine via the installed P.T. bootstrap. To make this
happen a small interface was built that allows a laptop to set the state of 8 data bits, we now
tried to implement this idea!
The first blow to this plan was the fact that reader channel selection logic has been changed
in fact logic rack 2G is a complete rebuild. Unfortunately not to any existing standard in
either 1301 software or hardware command set.
The rest of the day was spent on my knees trying to understand the 36 way connector that
there seems to be little or no documented information on, Galdor added this I/O port but no
recorded use of it exists in the documentation.
The first result of this painful exercise was that we think we know how the socket is wired, and
by applying the signals from the laptop and interface we can see data getting into the "B"
As this PC interface was designed to drive a paper tape interface, we need to revise the logic as
the actual logic bieng driven is unknown and the drive levels seem to need a higher level
than normal. However it may be a way into the machine, the big drawback is the lack of a loader
for this route, it is a pity the tape reader route has been blocked, as we have a bootstrap for
that route. The second result of this excersise is that I was late home trying to get this
to work, and lost a floating 5volt PSU as it started to burn up either due to a short or
the old floating -6.3volt which is a problem interfacing to flossie. The third result is
that after working for over two hours on a socket only
seven inches above the floor, in a dark and cramped area, my knees and back are telling me
I should not be doing this at my age ! However we will try to document the connections we
found in the next dairy entry.
47th Episode:- 10/08/05
After the open day we had a problem with a power supply in the paper tape reader, a sealed
transformer has failed. Today a reworked PC power supply was fitted it now supplies the plus
12 volts line and seems to handle the current load. The voltage is a little low but useable!
We moved on to the problems Roger experienced with the paper tape reader gaining track 3
( bit 4 ), after a strip down of the elliot reader head and making up paper tape loops with
alternative one's and zero's punched. We traced the problem to a potentiometer in track 3's
read amp, the wiper has a dead spot and this was giving noise, moving the wiper has settled
it on a good part of the track and we are able to get a reliable setting.
A small period of time was spent on investigating Deck A, and after a little work the
main mechanics of the deck are working, and the servo's are running, this is another
contender to our stock of useable mag tape decks.
Flushed with this success we tried reloading Initial Orders onto the reserved bands of the
Drum. This involved reading paper tapes into flossie and then manually patching the code
in store to incorporate the paper tape bootstrap code !
The patched code was then written to the reserved bands on Drum One, a quick test showed we
had a working set og I/O's . An engineer's format punched card was placed in the card reader
and all five store locations had the correct code in store when it was read. We did notice
that a zone and numeric component had failed to shift correctly in the C register, this
is either a timing problem or a clocking problem in the C register.
However we do have initial orders re-written, this is most important as this is the bootstrap
which we need to move forward to testing and fault finding the DTU!
So the day closed on a high with a big milestone passed ! We can run bootstraps to load
code, now all we need is a route to load the code and ( of course ) the code itself !
Roger rang after this visit and invited us to a BBQ as part of the Car Rally Success,
unfortunatly I had a prior commitment, but when he mentioned the passing thought of Fireworks,
I suggested that perhaps the fireworks should be used to celebrate the Initial Orders Success !
46th Episode:- 27/07/05
The first question this visit is what is the most important outstanding problem, we decided that
the tape reader needed to be checked as the power spooler sometimes did not work and
the read head had given Roger a problem gaining 4 bits over the weekend. Yes you
guessed it! Neither problem could be reproduced. The tape spooler worked without a hitch,
and the read head behaved itself perfectly. Now if only the drum would work from cold we
could reload the reserved bands.
Whilst waiting for the drum to warm up, we noticed a strong smell of
burning ? " Panic " , however it proved to be a transformer in the plus 12.6 volt psu
in the back of the Tape Reader, sad to say even after we did everything to isolate the
load on the transformer, its was the transformer which was getting too hot " we suspect
a shorted winding within the sealed case ". So no reader was now available, but of course
at that point we found we could write and read from the Drum with no problem, ghost and the
peri exerciser program loaded and worked first time.
Ok we know when we are beaten, so we started to re-fit the rack in 5H( the upside down one )
in episode 39. Roger has removed the rack the previous weekend and after a lot of work, we
risked a power up and flossie was very sick, and again we started to smell hot wires and a
brief panic as we powered down, after a lot of isolating we found a dead short on the rack,
removed short and re established not only the connections to Rack 5H, but also the interrupt
in bay 9J21 ( this was isolated over two years ago to stop a permanent interrupt from the DTU )
see episode 6 in the 2003 diaries.
The day closed with a chance to try the DTU and see if we could read a mag tape,
with a little care in choice of tape and deck we think we can read a tape header label
from Tape 140 on Deck D, it looks as if it might be a valid header label, we need to
decode it first though!
( Hey thats Real Progress ! )
A short visit after the open day and a chance to try to isolate the problem which almost
stopped the open day happening. We have been dumping current into the third and fourth
Barn doors and it eventually started blowing a 5 amp fuse in the plus 22.5 volt Psu.
After mapping where each connection to the supply went we monitored the current and
it seems that most of the problems are just the A7 drivers which have cooked up resistors
on the board. We finished the exercise with the third barn door connected but still failing,
to work correctly, however it was not draining current, out of the supply.
We also tidied up the second feed rolls on the card reader and the Tape Reader spooler was
set up, Roger has had problems with this not working on occasion.
" Link to the 2005 Open Day Page "
last try before the open day, and we have a problem which
is blowing fuses in the store power supply, Roger warned me about this, he discovered it on
the sunday before, and rang me at home. So placing a meter in circuit gives current drains
over nine amps. The fuse is only 5 amps so its not surprising the fuse blows from time to
time, with the open day looming close we decided to isolate the non functional Barn Doors,
so the +22.6 supply has been isolated, at the connection to the barn door in bay 9.
After this a lot of dressing Flossie up for the public day continued, and we finished with
the smell of polish in the air instead of soldering iron fumes, or the reek of oil.
general repositioning of the periperals, and the
main area in front of the machine has been tidied today, also some dust sheets applied
to the surrounding areas, a quick check of which Mag Tape decks will and wont work for the
open day, and the Demo program of the day was finished and written to the drum. the machine
does look better for the work. I even strimmed the grass around the approach area, it is getting
to be a bit of a jungle. A last try to fix the punch proved a fruitless exercise, so no
punch will run on the open day, which is probably good as it makes one hell of a racket, and
does make people jump when it starts up !
We repositioned the Card Punch today and tried to produce some entry tickets for the
open day in the form of punch cards. Yes you guessed it we should not have moved the punch.
It seems the timing has changed and we think we wont be able to fix this in time for the
open day. However the extra space it has provided has proved worth while.
Roger had rung on the 18th to say that it
seemed that the drum was trying to work ( when it had warmed up ), this is very good news as
it means we only have one fault ( we hope ) between us and a working drum, but the fault
is temperature sensitive. So whilst waiting for the drum to warm up, I worked in IAS area
looking for address line failures, none found.
Analysis of the tape Punch
board says, we need to replace all the chips ( it is a special made by the previous owners )
Flossie does not use TTL chips in her original design. Not a productive day, at that point
but at least there are no address line failures into the store, so we can keep fault finding
each Barn Door as a seperate problem.
The drum finally started working, and we are indeed able to write and read when
it is warm, we can read when it is cold, but only what has been written when the drum was warm.
So good progress of sorts, and a high note to end the day on !
Roger had worked on the machine over the weekend and found that a supply required for the
Tape Punch to work was broken, we fitted a new supply and attached the red wire to the Plus
side of the supply and the black wire to the Negative side of the supply to the board.
Some time later we discovered that, that had been too obvious, when we removed the board,
all of the TTL logic was red hot, yes the supply was reversed, the red wire was the
Negative and the Black wire was the Positive.
The words uttered at this point, shall not be recorded here !
To clear the air a little, as it had just become a little blue, we started working on the DTU
and interrupts, this is an old problem which we would like to resolve.
The machine gives permanent Data Transfer Unit interrupts and locks out the CPU, we have
isolated this signal a long while ago, now we are trying to find what is causing the solid
interupt and tracing down the signals from the 1900 interface we found a rack in 5H which was
giving us the wrong signal. At first we thought it was the fact that we have no 1900 devices
attached to this machine, however we noticed that an incorrect board had been fitted sometime
in the dim and distant past, whilst trying to change the board. it was also discovered that
the whole rack had been fitted " upside down ".
Ok time to stand back and re-asses this problem, we think that the rack bieng upside down
has saved the day, as it means that no power has been applied to the rack, only logic signals.
But it is time to think about this one, as its a lot of work to do and we want to make sure we
dont get it wrong when we correct the Rack.
Now we are able to work on the Set up amplifiers in the Card Reader Logic, and whilst the new
parts fitted seem to work, we were able to read cards and check the 1st two columns are reading
correctly. So progress of sorts, although we need to understand the actions of this modified
decoder and its impacts on existing card packs, like engineers test software.
Work started with the fitting of 6volt 6watt bulbs, in the card reader. Roger had found a source,
as these bulbs are used in older style VolksWagen, still uses 6volt electrics. However
even when we replaced the bulbs most still did not work, this was traced to a fuse in the
power supply of the card reader ( Opps ! )
We then moved onto trying to read data into the reader and found that some read amps had failed
in the process we discovered another modification to the card reader decoder, which blocked
the removal of the boards, so we could not even start the repair.
A rewire of the logic in the card reader bay now allows the removal and repair of the boards
in question. This now lets us read cards but with the new decoder still in place.
Finalising the work on the card reader, we fitted the freshly tyred 3rd set of feedrolls, now
with nylon tyres. Then the reject hopper selecting fingers and mechanism was set up.
We then fitted layers of inner tube to the stacker roll of the card reader, after the casting
was cleaned up. Calculations showed we needed five layers, these were fitted and then the
whole assembly was trimmed in the lathe. See the finished staker drum below:-
After re assembly of the Card Reader, we discovered that 5 layers was just too much, so
we had to sacrifice one layer of rubber ( now a spare layer ).
After final set up, we wound the card reader over by hand, and it fed a card down the track and
into the stacker, thank god the timimg of the machine had not been lost.
However now we have discovered a simple fact, all that hammering away has caused us to loose
the filaments in 4 out of 5 of the lamps in the photo_cams. Oopps.. !
So its hunt the 6 Volt 6 Watt bulbs time now.
Work on the CPU starts next visit !
Some careful drilling today gave us a succesfull removal of the taper pin holding the
stacker drum bevel gear. The result is that we have been able to take the drum assembly, off of
the machine and can now review the chance to repair. The best bet for the stacker drum
is to use layers of car inner tube to build the surface up to the required depth, this will
be used in place of the original neoprene moulded surface.
The third feed rolls are a
different problem and we have elected to make nylon tyres to replace the original neoprene
We tried some Mylar tape in the Tape Reader and it seems all the track amps are working,
with all bit combinations bieng transfered into the B register from the Tape.
Some work now on the Tape Punch Mechanism, first the ability to feed tape and lace
the mechanism up. Now O.K. However the Punch driving logic seems defective as it tries to
punch all the holes all of the time, another problem to add to the list!
Very little work on the main CPU, this visit, which at least seems to be staying stable at
Back to the mechanical problems on the card reader.
Now the taper pin problems are comimg to a head. the pin has already been replaced, sometime in
Flossie's history and may not be lined up ! This could explain why it is not responding to
considerable hammering, with pin punches! and we may HAVE to drill it out !
Examination of our "Spare" reader, shows the same decomposing rubber problems, so we agree
that we must focus on the pinning problem first ! Work continues and the last rubber cable to
the compressor is replaced, a test of the reader shows we have solved another problem and even
contactor worked first time, now we move onto the Line Printer !
This seems to be in a good state of preservation, well greased many years ago ! But more
rubber mains cables are found, so work will need to continue here !
Attention now turns to the Paper Tape Reader, which has been blowing fuses when we tried it last
year. The problem proved to be a mains filter, so the supply was re-routed via another source and
then the reader was successfully powered up, we even managed to read a few characters into the
machine from the read head !. Just to prove life still had a few downs we did blow a fuse, but
after all those years, I think it was allowed to ! "Don't You?"
Attention turned to the Computer again, and we were happy to find it still behaved as well as
last visit. We even managed to power up the Drum and read some of the data written during last
years work. To be fair we also had some read failures but all in all the investment in work
over the previous years are now showing in a more reliable computer.
The first visit of the year and its time to check out all the mechanics of the peripherals.
So the Card reader has the following jobs to do, first the old rubber Mains Power cables
have to be replaced, then we have to get the rest of the decomposing rubber components
need to be sorted out. All the while whilst working on these items, the mind keeps wondering
how much of the electronics have survived the winter hibernation.
But forcing our mind back on course we replace the internal cables within the card reader,
and then discover the taper pins fitted to the reader drive shafts are solid, one in paticular
will not drive out. Plans to drill the pin out prove just how hard this is going to be.
The day ended with us testing the wiring and checking that the three phase motors run in the
correct direction. To do so we must power up the machine, we are greeted with a lot of the
machine running and we are able to both make the reader ready and issue feed orders
( 380002 )
Now we cannot resist trying the computer out and putting it through its paces.
After some problems with the Contactor in the reader ( who knows when it last worked ) we
discovered that the main computers Mill seems to be functional and even some store, enough of
the machine seems to be running for us to code up " Ghost " a simple loop that confirms the
mill functions including the hardware multiply.
This is a good sign after the years of work and we take it as a sign that all the work has
not been in vain, Flossie has awoken from hibernation in "Not too bad a state".
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