TF536 buffers

[Hsommer]

I am trying to install buffers om my lovely TF536 card, because I want to mount the CF card adapter at the back of my A2000.
I am using the 74VHC245FT from RS, part no. 896-2622.
The card is working perfect before installation of the buffers.
I am removing the 6 pcs. RN's just below the buffers(other side, 2 RN's for each buffer).
The three buffers are installed in footprints for IC4, IC5 and IC6.
Orientation of the ic's is correct, pin 10 GND and pin 20 5Vdc.
When I boot with the buffers installed, the CF card is not detected and the kickstart start up is displayed.
The TF536 is starting(colorbars flashing at start up).
Now I removed the buffers and installed the RN's and CF card is working normal again.
Any help would be appreciated.

Rgds
Henrik

TL;DR Summary of issue. Rev 2b supports buffers. Rev 2 (no b) does not without a modification. To Fix Lift pin 1 (DIR) on IC6 and connect the lifted pin to pin 2 (VCC)

[terriblefire]

You will have a soldering issue or a dead buffer chip. In either event we cant really help you much.

[Hsommer]

Thank you for the reply, I just wanted to be sure that there was nothing more into this modification, than removing the 6 RN's (RN5 to RN10) and then soldering the 3 buffers IC4, IC5 and IC6.
I tried to solder 3 different sets of buffers, 2 sets of Toshiba 74VHC245FT RS no. 896-2622 and one set of nexperia 74VHC245PW Mouser no. 771-74VHC245PW118, but no booting from IDE.
I checked all connections from buffer to the CPLD and to the IDE pins, no shorts between pins or open connections, between CPLD - buffers - IDE pins.
Could it be a problem with the buffer, interfacing 3.3V and 5V mixed(trigger level?)
Which excatly buffers working, are used by others?

Rgds
Henrik

[alenppc]

Which excatly buffers working, are used by others?

You should use Mouser Part no. 771-HCT245PW118

[Hsommer]

Thank you, I'll try to order some Mouser Part no. 771-HCT245PW118.
I had some progress...
I removed the IC6 and mounted the RN9 and RN10, now booting with IC4 and IC5 mounted.
So my problem is IC6, tried another new unused one(74VHC245FT), still not booting with that installed.
Checked connections again...
I have the revision 2 PCB.
Anybody have a diagram for this?

Rgds
Henrik

[Hsommer]

Which excatly buffers working, are used by others?

You should use Mouser Part no. 771-HCT245PW118

Just tried the Mouser Part no. 771-HCT245PW118 for IC4, IC5 and IC6, no luck.
Using this HCT IC the A2000 is just rebooting all the time(rainbow, then reset, looping).
When removing IC6 and mounting the RN9 and RN10, the A2000 is booting.

The status is:
IC's from the BOM: Mouser 771-74VHC245PW118 and RS 896-2622 74VHC245FT not working as IC6.
IC NOT from the BOM: Mouser Part no. 771-HCT245PW118 not working as IC6.

I didn't build this card, maybe a firmware problem? Or fault in the PCB?
I saw another post in here with the same issue:

viewtopic.php?f=76&t=5141

Rgds
henrik

[terriblefire]

Firmware shouldnt matter. I've never personally put the buffers on.

[exxos]

Have you continuity checked from the resistor pack under IC6 to IC6 itself ? The resistor pack is basically in parallel to IC6. maybe there is a bad via to IC6..

(note RP9 only has 3 resistors used).

[Hsommer]

Have you continuity checked from the resistor pack under IC6 to IC6 itself ? The resistor pack is basically in parallel to IC6. maybe there is a bad via to IC6..

(note RP9 only has 3 resistors used).

Thank for the reply.
Yes, I tried several times to check for continuity(and shorts), between the IC footprints and the RN's footprints, everything looks fine...

[exxos]

Yes, I tried several times to check for continuity(and shorts), between the IC footprints and the RN's footprints, everything looks fine...

Also you checked IC6 to the IDE port ?