[RKP Chennai]

Hi Pentaxians,

This is my first post, so please guide me if I am posting this in the wrong thread.

Few months ago, I bought a used K3 with no power issue. I thought I can try to solve the issue by opening the camera and find the faulty component within the DC to DC converter and try my luck to change it hoping that it will work with a midas touch ):-. I have found some components short to ground (GND). I have attached pictures depicting the suspected fault with yellow and red colour and green for good. I tried to isolate capacitor and diode which were initially showing short to GND but up on testing it with one side disconnected from circuit it showed normal findings. I have also looked at the PMIC chip (2 nos in K3, 1 is good and the other looks faulty). I have attached the schematic for BD9865WMV. The red oval ring showing 2 wires are showing short to GND. The wires shows + and -. I need advice from you guys regarding how to strategically find the component(s) which are faulty.


Regards,
RKP Chennai

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[AstroDave]

I suspect you are in uncharted territory!! I doubt that even Pentax/Ricoh tries to fix these boards - they probably get tossed and replaced with a new one.

[lsimpkins]

I hate to be another downer on this, but without a full schematic of the board, your chances are minimal of correctly diagnosing the failed component(s). And you don't have a schematic of the power management chips, you have the pinout and pin function tables. Without a proper schematic and/or parts list it will be difficult to identify the needed performance parameters of even the simple diodes, resistors and capacitors. Finally, based on my career in the semiconductor and electronic components industries the most difficult task might be to actually acquire the needed replacement part(s) if they are not simple r,l,or c components. At best, you might need to acquire a suitable donor K3 that has a different issue and swap out the whole board. Best of luck with your efforts and let us know how you make out.

[RKP Chennai]

Thanks for your reply Guys,

I am trying all sort of ways to identify the faulty components. Yes , without the schematic it's very ambiguous in finding the fault. I wonder if any Pentax dealer sell repair manuals for K3. I am also trying to seek out fellow pentaxians experiencing similar problems and find possible economical solutions...

[reh321]

Few months ago, I bought a used K3 with no power issue.


RKP Chennai

You mean that no matter how you manipulated the switch, the body showed no signs of being powered??

How would you distinguish this from a processor issue?

[c.a.m]

I need advice from you guys regarding how to strategically find the component(s) which are faulty.

Welcome to Pentax Forums!

Sorry, I can't help with diagnosing the problem(s). However, this place has a K-3 parts list with exploded diagrams: Pentax K-3 Parts List Digital SLR | USCamera Pentax Downloads | Parts PlusUSCamera

- Craig

[RKP Chennai]

You mean that no matter how you manipulated the switch, the body showed no signs of being powered??

How would you distinguish this from a processor issue?

I did a tap on battery to find the current consumptions with each buttons pressed. When the power button is off and while inserting the battery i could see current value of 279microamps. The value starts to go down as if there is a current leak somewhere in the circuit. Also I did see brief spike in current consumption with power button on and depressed. No indication light with SD card insertion on either slots. I did find watching this video very useful in identifying/narrowing down to defective area. FixYourCameraORG

You Tube

You Tube

---------- Post added 01-01-20 at 10:16 PM ----------

Welcome to Pentax Forums!

Sorry, I can't help with diagnosing the problem(s). However, this place has a K-3 parts list with exploded diagrams: Pentax K-3 Parts List Digital SLR | USCamera Pentax Downloads | Parts PlusUSCamera

- Craig

Thanks Craig, I did buy the parts list from them but not much useful as there is no PCB schematic. It does have wiring diagram but not useful at this time. Thanks very much for the input. Still hoping that I could buy the schematic and try worthfully.

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Last edited by RKP Chennai; 01-01-2020 at 03:19 PM.

[gaweidert]

Sadly, wiring diagrams are a thing of the past. The modern electrical ship is simply too complex to build a diagram for. Field manuals would be measured in how many feet of shelf space that they take up With modern CAD systems, the computer keeps track of all that in it's memory. When I was in field service about the only wiring diagrams available on newer equipment were the cable layouts used to manufacture the connecting cables. Pretty much worthless. Chasing signals around can get frustrating real quick. Hence the concept of the field replaceable unit (FRU). Defective boards are returned to be repaired. Or "re engineered" in modern engineering parlance.


I do commend you endeavors.

[RKP Chennai]

Sadly, wiring diagrams are a thing of the past. The modern electrical ship is simply too complex to build a diagram for. Field manuals would be measured in how many feet of shelf space that they take up With modern CAD systems, the computer keeps track of all that in it's memory. When I was in field service about the only wiring diagrams available on newer equipment were the cable layouts used to manufacture the connecting cables. Pretty much worthless. Chasing signals around can get frustrating real quick. Hence the concept of the field replaceable unit (FRU). Defective boards are returned to be repaired. Or "re engineered" in modern engineering parlance.


I do commend you endeavors.

Hi gaweidert, Thanks for your input. Yes I strongly agree to the point that time efficiency is of paramount importance in todays technology. But still longing for problem solving if gven the right direction. Even getting schematic for basic Pentax DSLR is very difficult. Hope somebody can point me to the source. Thanks

[uttam.hathi]

there are fuses on board, could you identify them

[Iron]

Hi Pentaxians,

This is my first post, so please guide me if I am posting this in the wrong thread.

Few months ago, I bought a used K3 with no power issue. I thought I can try to solve the issue by opening the camera and find the faulty component within the DC to DC converter and try my luck to change it hoping that it will work with a midas touch ):-. I have found some components short to ground (GND). I have attached pictures depicting the suspected fault with yellow and red colour and green for good. I tried to isolate capacitor and diode which were initially showing short to GND but up on testing it with one side disconnected from circuit it showed normal findings. I have also looked at the PMIC chip (2 nos in K3, 1 is good and the other looks faulty). I have attached the schematic for BD9865WMV. The red oval ring showing 2 wires are showing short to GND. The wires shows + and -. I need advice from you guys regarding how to strategically find the component(s) which are faulty.


Regards,
RKP Chennai

This is a bit tricky. I am not sure if it's just a sheen on the photo but around the SKHynix chips, there seems to be a trace of liquid relief. It's either those parts are checked or the whole board is replaced. Cheers.

[RKP Chennai]

there are fuses on board, could you identify them

Fuses are ok. Voltage is going in to the power controller. Thanks

---------- Post added 12-29-22 at 05:10 PM ----------

This is a bit tricky. I am not sure if it's just a sheen on the photo but around the SKHynix chips, there seems to be a trace of liquid relief. It's either those parts are checked or the whole board is replaced. Cheers.

I am sure the water damage look adjacent to the SKHynix chips were light reflections. Thanks

[lotech]

You are doing something unthinkable to most of us Pentaxian, I even not dare enough to replace the backup battery ! I broke some tiny and fragile flat cables while fixing tablet and notebook keyboard. Although I'm from electronics background my tools and eyes are not good enough for handling tiny components and parts, how old is your camera ? mine is 8yrs+ old. Btw if you can fix that circuit board I'm sure fixing the SDM motor is piece of cake to you ha ! good luck fixing !

---------- Post added 01-04-23 at 01:17 PM ----------

Hi Pentaxians,

This is my first post, so please guide me if I am posting this in the wrong thread.

Few months ago, I bought a used K3 with no power issue. I thought I can try to solve the issue by opening the camera and find the faulty component within the DC to DC converter and try my luck to change it hoping that it will work with a midas touch ):-. I have found some components short to ground (GND). I have attached pictures depicting the suspected fault with yellow and red colour and green for good. I tried to isolate capacitor and diode which were initially showing short to GND but up on testing it with one side disconnected from circuit it showed normal findings. I have also looked at the PMIC chip (2 nos in K3, 1 is good and the other looks faulty). I have attached the schematic for BD9865WMV. The red oval ring showing 2 wires are showing short to GND. The wires shows + and -. I need advice from you guys regarding how to strategically find the component(s) which are faulty.


Regards,
RKP Chennai

Btw do you know which pin of the GB-5 grip responsible for AA battery power ? mine failed to work suddenly even with Lithium cell, so that I want to try AA but didn't work either, and I found a 'sunk pin' contact at the grip I believe is for the AA, it's more easy to fix so I'll start there, thanks !

[RKP Chennai]

Thanks for your reply and some new tips. I am planning to replace one of the PMC in the next few weeks. I will update here of the process and the outcome. 🤞