• Please review our updated Terms and Rules here

Cbm dual drive 3040 disk - two red lights

It shouldn't be all empty...

Of course, you now know that FF means that it is highly likely that the EPROM programmer can't read the EPROM correctly...

Which specific 2716 setting are you using on the programmer? You didn't select a Texas Instruments TMS2716 did you? Please don't!

Dave
 
dave_m said:
You should be able to read a 2316 ROM as a 2716 EPROM without adapter.
Click to expand...

Not quite.

The chip select pins on these 23 series ROMs could be defined as active-high or active-low at the point of manufacture so you always have to look at the schematic to work out how they have been defined. The 3040 schematic shows that chip-select pins 18, 20, 21 on the 2316 used in UK6 position are all active-low whereas a 2716 reader will hold pin 21 high during read, so that is why it will not read as a 2716.

We need another adaptor, this time one which connects all pins of the top socket EXCEPT pin 21 straight through from top socket to bottom socket. Pin 21 of the top socket should be connected to pin 12 of the bottom socket instead. Then Desperado will be able to read the UK6 2316 as though it is a 2716.

If this is not clear I will modify my original adaptor sketch to show what I mean, but I am away from my main computer today so that would have to wait for a day or so.
 
daver2 said:
It shouldn't be all empty...

Of course, you now know that FF means that it is highly likely that the EPROM programmer can't read the EPROM correctly...

Which specific 2716 setting are you using on the programmer? You didn't select a Texas Instruments TMS2716 did you? Please don't!

Dave
Click to expand...
No Dave...i used 2716 setting!
 
SiriusHardware said:
Not quite.

The chip select pins on these 23 series ROMs could be defined as active-high or active-low at the point of manufacture so you always have to look at the schematic to work out how they have been defined. The 3040 schematic shows that chip-select pins 18, 20, 21 on the 2316 used in UK6 position are all active-low whereas a 2716 reader will hold pin 21 high during read, so that is why it will not read as a 2716.

We need another adaptor, this time one which connects all pins of the top socket EXCEPT pin 21 straight through from top socket to bottom socket. pin 21 of the top socket should be connected to pin 12 of the bottom socket instead. Then Desperado will be able to read the UK6 2316 as though it is a 2716.

If this is not clear I will modify my original adaptor sketch to show what I mean, but I am away from my main computer today so that would have to wait for a day or so.
Click to expand...
ok i try to make it, thanks!
 
SiriusHardware said:
Not quite.

The chip select pins on these 23 series ROMs could be defined as active-high or active-low at the point of manufacture so you always have to look at the schematic to work out how they have been defined. The 3040 schematic shows that chip-select pins 18, 20, 21 on the 2316 used in UK6 position are all active-low whereas a 2716 reader will hold pin 21 high during read, so that is why it will not read as a 2716.

We need another adaptor, this time one which connects all pins of the top socket EXCEPT pin 21 straight through from top socket to bottom socket. Pin 21 of the top socket should be connected to pin 12 of the bottom socket instead. Then Desperado will be able to read the UK6 2316 as though it is a 2716.

If this is not clear I will modify my original adaptor sketch to show what I mean, but I am away from my main computer today so that would have to wait for a day or so.
Click to expand...
You were right Sirius, I made the adapter and I was able to read the PROM immediately ... the device gave verification ok ..... now I don't know what could be faulty ... I'm desperate!
 
You are getting very good at this ROM verification game, well done.

You must be the only person I know who feels unhappy when a component turns out NOT to be broken. :)

The repair process is always one of elimination, you check something, it's OK, you check something else, that's OK too, another thing, that's OK as well, eventually you find something which is not OK. You just have to be very patient.

Now that we know the firmware seems OK, I have no doubt Dave's brain is buzzing with ideas about what to look at next.
 
I read in the manual that the 6504 in UH3 could be faulty .... can this prom be read with the programmer?
 
I agree with SiriusHardware. Any part on the board being faulty will result in the disk drive unit not working in some way.

We now know an awful lot about what DOES work. Unfortunately, we can't rule out the RAM chips at this time because the piggyback test is not that good. It was worth a try though...

You also found out how to use your logic probe more successfully - now you know that you have to power it from the SAME supply as the devices are powered from that you are trying to measure.

We also didn't see any SYNC activity from the 6502 at one point - and now we do. This indicates to me that something was wrong, but has now been 'fixed' - which makes me think that there is (still) a socket problem...

The 6504 is not a ROM - it is another CPU...

Check (with your oscilloscope) that you have a 1 MHz clock on pin 27 (clock in) and a 1 MHz clock on pin 28 (clock out).

Check the signal on pin 3 (/IRQ) with your logic probe. Is it HIGH, LOW or PULSING?

Next, check pins 26 (Read/not Write) and pins 5 through 17 (address lines) with your oscilloscope for signs of activity.

Also check UA3 (74LS42) pins 1 through 7 AND pin 9. Are they HIGH, LOW or PULSING?

I would then go back to UE1 (6532 RIOT) and remove it from the board.

When you turn the disk drive on - all 3 LEDs should come on. Is this the case?

Next (with a 100 Ohm resistor or similar) connect the following pins of the UE1 socket to 0V (pin 1) via the resistor:

UE1 pin 18. The ERROR LED should extinguish.
UE1 pin 19. The ACT 0 LED should extinguish.
UE1 pin 21. The ACT 1 LED should extinguish.

These three (3) pins of UE1 each drive an open-collector 7406 inverter to actually drive each LED. When the input of the 7406 inverter is HIGH, the OUTPUT is LOW - and I think this should illuminate the associated LED.

If this test is fine, then we know for sure that what we are observing on the LEDs is 'real'...

Put the 6532 device back into UE1 at the end of this test (with the power OFF of course).

After that, I would start to swap the socketed major devices (such as the 6532 at UE1 and UC1). Either that, or swap them one at a time for a known good device (if you have any). If going for the swapping method - if you exchange UE1 and UC1 and observe no change - it is vitally important that you swap them back again so as to not introduce another change/unknown...

Dave
 
Last edited:
daver2 said:
Check (with your oscilloscope) that you have a 1 MHz clock on pin 27 (clock in) and a 1 MHz clock on pin 28 (clock out).

Check the signal on pin 3 (/IRQ) with your logic probe. Is it HIGH, LOW or PULSING?

Next, check pins 26 (Read/not Write) and pins 5 through 17 (address lines) with your oscilloscope for signs of activity.
Click to expand...
Hi Dave, on cpu 6502 right?
 
daver2 said:
Check (with your oscilloscope) that you have a 1 MHz clock on pin 27 (clock in) and a 1 MHz clock on pin 28 (clock out).
Click to expand...
Yes i have 1 MHz clock!
daver2 said:
Check the signal on pin 3 (/IRQ) with your logic probe. Is it HIGH, LOW or PULSING?
Click to expand...
No signal here!! :(


daver2 said:
Next, check pins 26 (Read/not Write) and pins 5 through 17 (address lines) with your oscilloscope for signs of activity.
Click to expand...
pin 26 and 5 to 17: no waveform but only high signal :(
daver2 said:
Also check UA3 (74LS42) pins 1 through 7 AND pin 9. Are they HIGH, LOW or PULSING?
Click to expand...
1 to 7: HIGH
9: LOW
 
daver2 said:
Next (with a 100 Ohm resistor or similar) connect the following pins of the UE1 socket to 0V (pin 1) via the resistor:

UE1 pin 18. The ERROR LED should extinguish.
Click to expand...
I found a 10 ohm resistor!

UE1 PIN 18 TO PIN1 RESISTOR= CENTRAL LED OFF
daver2 said:
UE1 pin 19. The ACT 0 LED should extinguish
Click to expand...
LED ON RIGHT DRIVE OFF
daver2 said:
UE1 pin 21. The ACT 1 LED should extinguish
Click to expand...
LED ON LEFT DRIVE OFF
 
daver2 said:
After that, I would start to swap the socketed major devices (such as the 6532 at UE1 and UC1). Either that, or swap them one at a time for a known good device (if you have any). If going for the swapping method - if you exchange UE1 and UC1 and observe no change - it is vitally important that you swap them back again so as to not introduce another change/unknown...
Click to expand...
I have already done this test with some 6532s that I had spare but I have not seen any changes :(
 
You must log in or register to reply here.
Back
Top