Agilent E4407B Repair , No Video

[analogRF]

So I did a comparison of a known good Flash SIMM and the one acting up
table below shows the comparison

All measurements done from Pin1 (Gnd) to each of the other pins

the only thing to shows is that the datalines all show a lower resistance but otherwise pins are consistent in my view yet the bad one does not work

Sandra
did you ever fix the cpu board or the flash module?

[analogRF]

so replacing U74 did not help, right?
what information do you think the U74 holds?

did you replace all of the flash chips on the flash module and still it didnt work??

[perieanuo]

Xgecu released 10.29 of the software and added the flash support I requested.
I did confirm the flash on the CPU board was bad,  I did a multiple Read/Erase/Program/Verify on it and after 1 pass it failed.
The flash from the SIMM was OK.   But that Simm module still has problems.   if its put in I get the same original problem back
so any condition where the flash is as an issue results in same behavior

the board is fixed but that SIMM still causes problems
it's hard to find the SIMMs anywhere and Keysights current price is $506

I'm going to compare a known working SIMM to the one not working next and see of there are any differences.

if you got bad fw for main uC, you expect to trick the other chips inside written by the uC with fw loaded from a bad chip???
i don't get what you did, you have writen the bad flash in external programmer, put it back in his place and then reflash the SIMM flash?
that was the correct steps, but you're unclear

[smgvbest]

so replacing U74 did not help, right?
what information do you think the U74 holds?

did you replace all of the flash chips on the flash module and still it didnt work??

What mine ended up being was bricked.  it wasn't a flash issue but a really bad attempt at flashing it apparently give same response code as a bad flash chip
once I did a full clear of flash and memory using the switch method on the cpu board it started reading my floppy escalader disc and then it took the firmware load.

[analogRF]

so you think the original U74 and the flash SIMM were OK?

[analogRF]

Finally after a couple of month, I found some time to see what is wrong with this E4405B that I got
It does not boot. The backlight comes on which is pretty dim I think and stays on, fan is running. The floppy light never blinks
and I need to pull the plug to power it off.

I opened the case and turned it on. All the RED LEDs turn on and stay on (DS7-DS13) and the Green LED (DS1) which is marked as HRT BT
stays on and does not blink so no heart beat 

5V supply is present on the CPU board and I can only check -12V and +15V are present on the front panel probe power connector.
There is no place to check the power supply voltages, right?

according to the SM, DS7-DS13 all on means "start of the test" so it does not even get to bootrom checksum apparently.

anybody has any idea? any hint?

EDIT: the unit had never been opened since its last Cal. all seals were absolutely intact. So something failed on its own and I am the first one in

[analogRF]

CPU has clock and is not in RESET...so I am about to run out of ideas... any suggestions?

working on the CPU board is a pain in the a** and pretty much impossible for the most parts, so nothing much can be done in terms of measurements



I tried to figure out what kind of connectors attach it to the motherboard and tried to find
jumper ribbons with those type of connectors to bring out the CPU board but they cannot be found...each has 100 pins

[analogRF]

Does anybody know what exactly means when all LEDs are ON and stay on? even DS1 (HRT BT)?
can it be the CPU is dead?? I have seen many many non booting instruments but dead CPU I have never encountered.
I think it must be something else...

[smgvbest]

Sorry I am way late on this.   been having a bad time with my back.  just has a SCS implant done so hopefuly life will be getting better soon

All the LEDs on is the start of the Self Test. So it's' not getting past that point
the Service Manual has this starting on Pg37 with some other basic tips.

what brought mine back to life with a full clear of FLASH and SRAM memory.
But mine was in a different state than yours

Again sorry I did not reply sooner

BTW,  you can supply power to the card outside the machine and hook up the serial port on the card to see it booting.   allows for testing outside the SA
once it's' past the all LEDs out point and DS1 flashing you can put it back in



Sandra