Fluke 105 scopemeter Series II repair - Page 1
Forum section: electronics / repair

author: jchw4
author_rank: Regular Contributor
timestamp: November 08, 2019, 10:43:46 am
content: I bought Fluke 105 as a new toy. "Does not turn on", as usualAfter opening it was obvious that batteries leaked long ago, so it was probably stored as "non-working" for last 10 yearsBut since it's a toy, I will probably try to fix it.To check whether I can wash corrosion away, I decided to try vinegar on some smaller part.But given the amount of damage, I decided to try ultrasonic cleaning firstI don't have full-size machine, so before asking my friend for help with his large one, I put a top part of the LCD board into a tiny cleaner, so that the water covered only one row of the LCD drivers.I used 5% vinegar:water solution ~ 1:10, so it was probably .5% acidic.And I think that the result is pretty promising, I did not find broken traces, so the device could be repairable.Digital board seems to be 2-layer, so it is probably repairable.The analog board is in better state, but it's 4-layer, and two of the capacitors leakedThe damage is not too big, but the board is dense and also those 4-layers...The bottom of the analog board seems to be still full of flux, which I decided to wash away only around the damage.(Should I fully remove the old flux?)The connectors side has several large discrete components which are difficult to unsolder carefully, so I will probably leave it as it is.(Should I unsolder the front connectors and fully clean the board?)You can see the current analog board state on the last few photos. I removed a few components, and will probably replace more damaged resistors. But otherwise analog board seems to be clean.But I still have more questions than answers.- Are my ideas reasonable? Should I remove connectors and damaged parts (LCD drivers, battery, transformer, through-hole connectors, two RAM ICs) from the digital board and wash it in ultrasonic cleaner?What cleaning solution would you suggest? What procedure would you suggest?- Should I also remove flash IC (it does not look very damaged though)?- If I remove it, how can I dump it?It's Intel 28F004BX-T80, 4-MBIT (256K X 16, 512K XBOOT BLOCK FLASH MEMORY FAMILY.Can something like TL866II dump it?My current plan is to remove damaged parts, wash the board in vinegar solution, check visible vias and traces, solder parts back (or replace with new?), and try to start debugging it.What am I missing?BTW, does anybody have service manual for it? One can find old Fluke/Philips 93/95/97 scopemeter service manual, but the board layout is very different.In the review threadhttps://www.eevblog.com/forum/blog/eevblog-430-fluke-91-scopemeter-teardown/somebody posted two pages from the correct service manual, but otherwise I could find nothing.Any ideas?

author: rvalente
author_rank: Frequent Contributor
timestamp: November 09, 2019, 03:26:34 pm
content: Thats a very extensive damage, but I believe its reparable. I would keep washing it with just regular soap and baths of citric acid/vinegar.Wash, dry, wash, dry... use an old tooth brush with the bristles cutThem I would try to power it on, probably the solder joints are weakened I would not risk them unless Is a confirmed bad part

author: jchw4
author_rank: Regular Contributor
timestamp: November 10, 2019, 12:26:10 pm
content: I did more cleaning of the digital board today. The result was good (only two vias were still blocked, i.e. I could not see through them).But then I found that many traces (~10) on the LCD side are broken, and a few vias that start under the LCD driver chips lost their connection.Luckily I did not find broken traced around the memory.So I will have to remove at least two LDC drivers to repair vias.It still seems doable, but a lot of handwork.