Indus GT - Diags, Part 2

{Preserved from a now-defunct Atari board}
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thark

Post by thark on Jan 23, 2016 at 2:15pm
hi fellow atarians, been fixing up an Indus GT today, anyone know which potentiometer adjusts motor speed? obviously its different to the 1050 - theres noVR2, but there are similar looking pots in there. save me reading forever the service manual if you know.

cheers!​

8bitbaz

Post by 8bitbaz on Jan 23, 2016 at 2:19pm
Just found this, buddy:

Motor SPEED ADJUSTMENT
The drive motor speed test checks to see if the speed is within the specified
tolerance. Theoretically the motor speed should be at 288 RPM plus or minus four
RPM. The recommended speed is 288 RPM plus or minus one RPM.
STEP1.Insert a diskette into the drive.
STEP2.Select the Motor Speed option of GT;DOC.
STEP3.Select the Index Mark speed check.
STEP 4. Locate R31 on the Analog Board (see Figure'6)9), This is the speed control
pot.
STEP 5. Adjust R31 until the motor speed is within 288 RPM plus or minus l RPM.
Attachments:
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thark

Post by thark on Jan 23, 2016 at 3:18pm
R31!! cheers baz! most helpful. i think brenski emailed me something but i aint checked yet so thanks to Brenski too -
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Post by thark on Jan 23, 2016 at 4:41pm
nice one - got my indus GT fully working! im also making progress on brenskis, i can get it to load disks if i hold the latch at the point it catches the disk - if i fully close the latch it hardly spins. the belt looks very worn so i have tried turning it inward out but hasnt made too much difference. im working on it - i have a spare old belt that should work. they are a real pain to fit but its doable. could also be motor problem of which i have spares too.
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Post by thark on Feb 14, 2016 at 8:58am
hi chaps, im in mid fix of brenskis GT. replaced a bad capacitor and put the steel belt back onto stepper motor. still getting same error code.
I belive its G3, but the digi display is a little tempramental, it looks like " l l 3" .

im fresh out of working zero sensors, so if anyone can shed some light on this type of fault? i have all needed caps to replace them all if need be, but they 'look' fine.

if it is the zero sensor then im needing one.

i havent tried removing and refitting the chips yet.

cheers for any ideas if you have any.
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Post by thark on Feb 14, 2016 at 9:01am
on one occasion it tried to seek and '16' came up on digi display, but usually the drive mech doesnt do anything. when it does it doesnt seek it just spins endlessly and the head does nothing. im thinking bad chip somewhere
​

admin

link to FSM

blog.3b2.sk/igi/file.axd?file=2011%2F7%2FINDUS_GT_FSManual.pdf

here's description of the error codes for the Indus GT

'G' = GET or read error,
'P' = PUT or write error
'F' = FORMAT error.

the numeric values are:-
3 = Lost Data Error
4 = Checksum Error
5 = Record Not Found
7 = Write Protect Error
9 = Verify Error


'E' = displayed when no error has occured (Hold down ERROR
push button while TRACK push button is pushed).

Disk errors G3, G4, G5, head need cleaning or disk has bad sector or alignment on the drive...

H3 is on the mother board..Try replacing the H6116 or 74LS244 (U19) first and/or U23)

The indus has built in diagnostics that run every time at power up.
If an error occurs, an alpha-numeric is displayed on the LED..

The C is displayed while the tests are running. H is displayed if a
test fails. Initially, C will flash and and quickly counts 3.

C1/H1 = Quick ram check.
C2/H2 = Z80A index registers test
C3/H3 = Floppy disk controller test.

After that, the led display should briefly read 00 before stepping up to 39.
If nothing of the sort comes up, then there is some problem with the Z80, ROM, PSU ICs or logic circuit.

You can also run level 2 Diags.
an SIO cable configured/shorted :-
pins 1, 2 and 7 shorted
Pins 3,5 and 10 shorted
Fit the plug,power on while holding down TRACK, ERROR and DRIVE TYPE buttons front panel buttons.
C4/H4 = serial bus interface bus test.
C5/H5 = Interrupt circuitry test
C6/H6 = Extented ram test.
This takes a while to complete
if successful, an E- is displayed.


A note (from reading the FSM) on how the C/H Diags work:-
C3/H3) Floppy Disk Controller Test *


The Built-In Diagnostics run a series of routines to test the Floppy Disk Controller. T
Running Order:

1. UART issues a FORCE IMMEDIATE INTERRUPT.
2. Z80A runs a short time delay loop for 52 microseconds via WD1770 with WD2797 running faster.
3. FDCs INTRQ line tests FDC for interrupts. FDCs INTRQ line is not tied to the Z80As IRQ line. Test will fail on no response from FDC.
4. FDC is issued a FORCED INTERRUPT command to clear the FORCE IMMEDIATE INTERRUPT condition.
5. Z80A waits 52 microseconds for the FDC response.
6. FDC status register read and clear the FDC interrupt.
7. Z80A waits 52 microseconds for FDC response.
8. FDC INTRO line tests FDC has cleared. Test will fail on no response from FDC.
9. FDC track, sector, and data registers (in that order) load from 00H, 01H, and 02H respectively. Next data, sector, and track registers (in that order) are checked for pattern changes. Any errors/mismatches reult in test fail. Finally test is re-run from 01H, 02H, and 03H respectively. Test process continues until final pattern FFH, 00H, and 01H respectively.
10. FDC track register copied to data register and a seek command is run. FDC will seek to the current track. Test checks that WD1770 is in Mode 1 and that the IP is re-run in status register. Test NOT required with WD2797.
11. FDC index pulse (IP) line set to active.
12. Z80A waits for >20 microseconds allowing for FDC response.
13. FDC status register verifies index. Fails if if index not verified.
14. FDC index pulse line is disconnected.
15. Z80A waits >20 microseconds allowing for FDC response
16. FDC status register verifies removal of the index. Fails if not verified

If any of these tests fail, "H3" will display on LED.

Further notes:
U19 and U23 are 2 74LS244 chips on the main-board and may be soldered. 74LS244 is an octal buffer/line driver for signal buffering.
(U19) buffering the Atari port signals and IRQ/DRQ signals internally (to the data bus). failure results in H3 (Halt in test 3) error code
(U23) located (electrically) between the 4 config switches on the back and the data-bus and the front panel switches and the data bus.

PSU should be meter read as out of range gives unexpected reporting/results.

if FDC at fault a chip swap is the fix. - swapping the FDC chip and RIOT.

Motor SPEED ADJUSTMENT (from Baz)
The drive motor speed test checks to see if the speed is within the specified
tolerance. Theoretically the motor speed should be at 288 RPM plus or minus four
RPM. The recommended speed is 288 RPM plus or minus one RPM.
STEP1.Insert a diskette into the drive.
STEP2.Select the Motor Speed option of GT;DOC.
STEP3.Select the Index Mark speed check.
STEP 4. Locate R31 on the Analog Board (see Figure'6)9), This is the speed control
pot.
STEP 5. Adjust R31 until the motor speed is within 288 RPM plus or minus l RPM.

ALIGNMENT:
The drive should automatically align.
The only time it may need re-aligning is after removal/replacement or loosening of the stepper motor.
to re-align
Insert a good disk - move the sensor back and forth (drive resetting, attempting to read the disk)you should do this until you locate the exact position.
The sensor tends to "miss" by a whole track - rather than a small section of a track, - making this a fairly easy fix.​

thark

Post by thark on Feb 14, 2016 at 6:33pm
head is fine, so it is H3. a chip is a gonner probably. what i thought. one of the chips is different. has a circle window in the middle. not seen it before.​

admin

it's not necessarily a chip fail. i know people on AAge who've re-seated them and all was fine - surely worth trying that first?​

thark

Post by thark on Feb 16, 2016 at 1:53pm
on brenskis advice - i will try reseating them and cleaning the sockets ect. sound reasoning as the age of them oxidisation surely gets onto the contacts.​

Bikerbob

Post by Bikerbob on Jun 6, 2016 at 1:12pm
Well I am going to continue in this thread since it is already here.

I am trying to get 2 - Indus GT drives up and running.

1 - Seems ok.. Boots .. gets through level 1 diag. no issues.. when using various disks I do seem to get G4 errors.
- Ran Diag on the basic dosxl disk that is the Indus diag disk.. Was tricky.. had to book with option down.. it will then load basic.. I then have to run a program named DIAGS.. even though the service manual says it should be called GT-DOC .. but I think DIAGS is a later version.
- All the tests in the DIAGS came up good.. speed was 288.5 it could read and write and verify.. init a couple of formats.. find track 0.. I am happy with this drive.. I think errors I get with this one will be more related to the media. I am going to get in and clean the head and lube the rail.

2 - Fails on boot - II0 error.. I think this is supposed to be H0 but the cross bar does not light.. even though it does work because I have seen it light other times. H0 is a ROM issue.. I did remove and reseat.. still same error. I have cleaned the head and lubed the rail, and pulled and reseated all connectors to boards.

- I have a friend with a eprom programmer. Mr.Martian on AA made a updated USdoubler style rom for the IndusGT.. I will try and reprogram the eprom with that or factory 1.2 I hope the ROM is programmable?? OR getting this error should I just move to a new EPROM?

- I had thought of maybe pulling the working ROM from the good drive and seeing if the bad one would then boot.. but the thought came that if its something else.. maybe I do damage to the good drive.. and in an age of retired drives.. not sure I want to risk a good one for a chance at a second. SO I think maybe I reprogram.. and go from there..

Opinions?​

8bitbaz

Post by 8bitbaz on Jun 6, 2016 at 1:43pm
From my experience of Indus GTs, fella, for what it's worth, they aint as "GT", ie. 'grand' or 'tourer' as they would like to think.

Me and Brenski have both noticed they are notoriously bad from a 'cold start', ie. pernickety, problematic and throw up spurious error messages willy nilly when first powered up...

They are NOT reliable drives, in our experience, in any shape or form, BB.

So, stick with it - they look the part - but are better once they've "warmed-up" - say leave em switched on for 5mins or so and then see if you have any improvement in terms of the G4 errors on drive 1.

It could be just crappy disks of course.

As for drive 2, yeah, try swapping good/suspect ROMs around and see if problems are replicated/you get one good drive from the 2, mate.

Whatever, we're always keen to help here and I'm sure Brenski, Baker and perhaps Thark will chip in with their hard-bitten experiences.​

admin

G3/G4/G5 - as said in my initial post are usually either
heads need cleaning/bad disks/head alignment

on the second drive - check that's not a "H3" - when some elements fail on the LED the H3 can end up looking like H0
when i wrote up this thread initially i couldn't find a H0
they only tend to come in 3 flavours
1, 2, 3


C1/H1 = Quick ram check.
C2/H2 = Z80A index registers test
C3/H3 = Floppy disk controller test.

to elimiate/identify the FDC as the problem, you can "swap in" a working FC100817 (WD2797)
from an Atari 1050 for the Indus 2797FDC
- they're interchangeable​

Bikerbob

Post by Bikerbob on Jun 7, 2016 at 12:07am
OK, so disk 1 is GOOD.

Disk 2 is the mech. I swaped some parts around and disk 2 gives me read errors.. there was no H0 error it was OO.. just the the top and bottom led bars on the left digit are burnt out.. and the middle one on the right. It does only have 1.1 rom.. but that was not the issue.

I have cleaned it.. and I know the couple of disks I was trying to read would read perfect on drive 1.. so I think I need to look at alignment.

back to the service manual.

James
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Post by Bikerbob on Jun 8, 2016 at 9:29pm
Anyone done the head alignment like they specify on page 6-11 of the manual? using the program and rotating the stepper motor?

I am going to try it as I dont have a scope.

James​

thark

Post by thark on Jun 9, 2016 at 6:00pm
indus gt are very fussy eaters - despite all problems noted, they are picky as hell and stubborn. ive replaced chips, capacitors,in indus gt and doesnt make no odds sometimes. i have one and it just arses about. some disks it will load, others it wont, but my 1050s all load same disks up perfect. i dont keep naff disks, only decent ones thsat dont leave crap on the heads. avoid like the plague. one day someone may find the real reason these drives are so pinickity.​

admin

as said above ....they´re super irritable. if the diags indicated an rpm speed that´s even close to ideal then Gt should still read disks. it´ll be formatting-writing that´ll be the issue​

thark

Post by thark on Aug 16, 2016 at 2:00pm
My next project is to fully recap an Indus gt. Capacitors are a plague in older devices and are the cause of most failures.​

Baker

Post by Baker on Aug 17, 2016 at 4:38pm
It seems like a lot of people are doing recapping projects with all their Atari stuff lately. The only time I've ever changed capacitors in any of my Atari stuff is for Supervideo 2.1 project. I've never had cap issues in 30+ years with my Atari's. Of course now I have to go knock on wood or they will all go bad on me at the same time! Just a few months ago I was saying how my 1084s monitor was still working like a champ after 27 years and not long after that at all, it went down on me. Maybe caps.

But I'm of the mind-set, "if it ain't broke, don't fix it," so I'll wait until caps start going out before I dive into a complete recapping of anything.​