Author Topic: need help with (not quite) dead Fluke 199C please  (Read 706 times)

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Offline analogRF

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need help with (not quite) dead Fluke 199C please
« on: September 02, 2019, 01:37:40 pm »
I've wanted to have one of these scopemeters for a long time but they are not cheap specially if you are in Canada. Finally I got this nice looking but dead 199C for a good price and I thought with service manual and schematics I can fix it  :palm:
The unit is in pristine condition with 2017 CAL sticker and inside is untouched but it does not power on  :palm:
I don't have the battery yet but with connecting the adapter, I hear a weak beep and that's it. Also by pressing and releasing the power key OR by pressing the ^ + > and power on , the same thing, a faint beep.
So I went through the steps in the service manual and did extra tests of my own based on the circuit operations and schematics and here is the result:
The 3V3GAR voltage that supplies the D-ASIC and all the memory chips is alive and solid. All three clocks (32KHz, 3.68MHz, 40MHz) are alive
Voltages and signals around the P-ASIC are all fine except that the POWERON (H) signal does not come from the D-ASIC thus the Flyback converter does not start so all power supplies are down.
The power on key functions properly (bit goes down with pressing)
There is a triangular 416.5KHz waveform at MS3603 (ROW1) which according to the manual is generated by the mask ROM. However, it is not 3.3V but 0.4V peak  :-//
There is not activity on the WDI pin of the watchdog IC  :palm:

So, I still believe the mask ROM is running and perhaps something happened to the memory module flash (corrupted, cleared, etc...) but the beep and 416.5KHz give me some hope that the D-ASIC is ok

Do you have any further suggestions as to how to proceed from here? Am I right about the D-ASIC? Is there any way to fix this?
I don't have the IR serial adapter but the actual serial TX/RX pins (3.3V) are available on the board.
I was thinking maybe I could connect them via a FTDI adapter and do the RAM check which is in the manual and maybe even flash the eeprom with new firmware?
I am new to this kind of thing, so any help, even with the very basics, is highly appreciated

there are so many of these scopemeters with similar symptoms being sold on ebay all the time and I thought people must have found a way to fix them but repair reports/diaries are non existent!
« Last Edit: September 02, 2019, 01:40:08 pm by analogRF »
 

Offline Samogon

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Re: need help with (not quite) dead Fluke 199C please
« Reply #1 on: September 03, 2019, 01:27:48 am »
Run over it. Same symptoms, installed known good ram/eeprom board and unit starts no problem.
Never seen FW for it
 

Offline analogRF

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Re: need help with (not quite) dead Fluke 199C please
« Reply #2 on: September 03, 2019, 01:36:24 am »
Run over it. Same symptoms, installed known good ram/eeprom board and unit starts no problem.
Never seen FW for it

may I ask where did you find the good memory module?
 

Offline Samogon

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Re: need help with (not quite) dead Fluke 199C please
« Reply #3 on: September 03, 2019, 05:19:22 am »
From good unit  ;)
 

Offline analogRF

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Re: need help with (not quite) dead Fluke 199C please
« Reply #4 on: September 03, 2019, 11:57:40 am »
I dont have access to any good unit so I need to find a way to fix this one.

I've seem comments on some Russian blogs (thanks to google translate) suggesting to re-heat/rework
the BGA memory chips on the module because apparently they tend to have dodgy ball joints
Maybe that's what is causing the problem but I am too afraid to put a heat gun on a flash eeprom.

Is that something that can be done safely without corrupting the data? Does heating it up actually fix a bad joint?


EDIT: I meant re-flow the BGA chip not rework!
 
« Last Edit: September 03, 2019, 12:41:38 pm by analogRF »
 

Offline Samogon

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Re: need help with (not quite) dead Fluke 199C please
« Reply #5 on: September 03, 2019, 05:17:20 pm »
My understanding was that data corruption is initial problem, i doubt reflow will help. I have one bad board on hand and can try it.
 

Offline Smith

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Re: need help with (not quite) dead Fluke 199C please
« Reply #6 on: September 07, 2019, 06:09:42 am »
I suspect data corruption too. I once "fixed" one of these that had 50% of the text on screen as garbled text. Rebooted multiple times, wirh and without battery. Scrambles text seems to look the same every time. Some features were not working either( I remember switching the ranges on one channel) . Especially on the input range switching this was annoying.

Somewhere in the menu there was a reset to default or something like that. That worked, after rebooting everything was working fine. A few years later it was still working fine. So maybe there is an EEPROM wich lost its settings. I do not think the settings would be stored in the main flash memory but of course the flash itself  can become corrupted too. I cant help you any further as it was not my scope.
Trying is the first step towards failure
 

Offline dacman

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Re: need help with (not quite) dead Fluke 199C please
« Reply #7 on: September 12, 2019, 11:22:16 pm »
One way to reset a (working) unit to factory settings is to turn it off, press and hold down USER, press and release Power On, and continue to hold USER until it beeps twice.
 

Offline ct1bxt

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Re: need help with (not quite) dead Fluke 199C please
« Reply #8 on: December 06, 2019, 12:09:51 am »
Hi analogRF,

have solve the problem ?
I have the same issue witch appears from nothing!!
I followed all the flow charts from service manual and can listen for the beep when push power, nothing more happens.
I have no battery inserted as it was off.
I do not sure if he can power on with a battery inserted or not. Some people on forums say that he need it, some others says he d'not.
If you need some values to compare, please, let me know
Regards
Rodrigo
« Last Edit: December 06, 2019, 03:01:16 am by ct1bxt »
 

Offline ct1bxt

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Re: need help with (not quite) dead Fluke 199C please
« Reply #9 on: December 08, 2019, 10:51:47 pm »
Run over it. Same symptoms, installed known good ram/eeprom board and unit starts no problem.
Never seen FW for it

Hi,

With the help of @analogRF and the people on this forum I was able to put mine work again cleaning the contacts of the flash memory module.
That kind of problem is very usual on PC memories modules. With a school rubber and some cleaning spay can be solve ah ah
Tks to all.
Rodrigo
 


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