Flashing LED -NeXTStation Color

[briano]

Folks
First post here and hope somebody can advise me
I have a NeXTStation Color - it starts - fan runs - HD spins - but no more than that
The red LED on the logic board initial gives one flash - the proceeds to flash 4 times and continues to do so.
I have visually checked for obvious issues such as leaking capacitors etc.
I have swapped the power supply from a known good unit.
I have removed, cleaned and re-seated the RAM modules.
But no luck...
Does anyone know what the 4 flashes of the LED mean?
Really would appreciate any advice
Brian

[marvin]

From an older Post I found the following list and the tip to pull battery if it blinks 4 times (NVRAM problem).

Code Select Expand

These are the blink codes defined in the firmware:

/* EKG LED blink counts */
#define BLINK_CRC1      1
#define BLINK_CRC2      2
#define BLINK_VRAM      3
#define BLINK_NVRAM     4
#define BLINK_DRAM      5  /* No DRAM in system */
#define BLINK_MACHINE   6  /* unknown machine type */

[andreas_g]

I can confirm this. I just "broke" the NVRAM on Previous. After the initial blink it permanently blinks 4 times. First thing I would do is checking the battery.

[ptek]

From an older Post I found the following list and the tip to pull battery if it blinks 4 times (NVRAM problem).

Code Select Expand

These are the blink codes defined in the firmware:

/* EKG LED blink counts */
#define BLINK_CRC1      1
#define BLINK_CRC2      2
#define BLINK_VRAM      3
#define BLINK_NVRAM     4
#define BLINK_DRAM      5  /* No DRAM in system */
#define BLINK_MACHINE   6  /* unknown machine type */

What header file is that from?

[briano]

Folks
A big thanks to all who responded.
Following the advice given I installed a total new battery (reading 3.3 Volts) on the logic board. Regrets - it made no difference.
As a test and based on the information provided - I removed all 8 RAM modules and sure enough the LED flashed 5 times as expected. So at least the logic board is reporting a genuine error.
Does anyone have and further guidance, which really will be most welcome?
I would be sad to see this lovely unit not in action...
Brian

[MindWalker]

If the blinks point to the NVRAM and new battery didn't help, perhaps you could try removing the battery for a longer time to ensure the NVRAM is cleared?

[briano]

Folks
Again - thanks for the feedback and sorry for any delay in replying - I an the GMT time zone
I removed the backup battery for 12 hours - same issue - 4 blinks of the LED.
I disconnected the floppy and well as the Hard Disk in turn - still the same issue :-(
Again - any ideas?
I really want to get this machine to work - it deserves it!
Brian

[andreas_g]

Maybe the real time clock chip or some connection to it is bad. Can you check the chip and its surroundings for anomalies?

The chip is labeled MC68HC68T1 or MCCS1850.

I am not an electronics expert. But maybe someone in here can provide instructions on how to measure the chip.

[marvin]

Another guess is that the battery contacts are corroded or short-circuited, so that voltage of battery does not reach its "goal".

[briano]

OK Folks
An update...
I have heeded all the advice provided.
In addition, I have removed the logic board and removed all removable components.
The board was then cleaned with IPA and blown dry with air
The board was heated to 100C
The board was replaced and re-tested
Same issue - 4 blinks of the red LED
Unless someone has a brainwave, my only option is to replace all the capacitors.
Does anyone have a list of the capacitors needed?
As mentioned before - out of respect, I really want to get this unit back in working condition.
Best regards
Brian