solved! fixing focus fk-2002 escom alps skcm blue

wanderhoden

08 Aug 2020, 00:33

greetings

found the board in a realy great condition...so i orderd the adapter it arrived today.plug all in and i tryd the keyboard the first time (key tester)...immediately i fall in love ^^so i playd a bit typing of the dead and stuff... it workd all good
6h later i noticed the keyboard startet to behave strange... keys dont work or sometimes they do ...random disconnect flashing lights ...a windows massage popd up saying somthing like the adapter cant provide enought voltage ...and than i smelld smoke :o
anyways ih managed to open the case without breaking anything (was not that easy) ...

iam not sure but ih think its the capacitor under the two c3 ones that blew up...did some onenow the value of that specific capacitor
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and here some more fotos from the boad
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in the mean time ih clean the keycaps and the case
hope someone can help me out
Attachments
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IMG_5333.JPG (2.3 MiB) Viewed 924 times
Last edited by wanderhoden on 09 Aug 2020, 01:00, edited 1 time in total.

User avatar
Polecat

08 Aug 2020, 03:09

wanderhoden wrote:
08 Aug 2020, 00:33
greetings

found the board in a realy great condition...so i orderd the adapter it arrived today.plug all in and i tryd the keyboard the first time (key tester)...immediately i fall in love ^^so i playd a bit typing of the dead and stuff... it workd all good
6h later i noticed the keyboard startet to behave strange... keys dont work or sometimes they do ...random disconnect flashing lights ...a windows massage popd up saying somthing like the adapter cant provide enought voltage ...and than i smelld smoke :o
anyways ih managed to open the case without breaking anything (was not that easy) ...

iam not sure but ih think its the capacitor under the two c3 ones that blew up...did some onenow the value of that specific capacitor

and here some more fotos from the boad

in the mean time ih clean the keycaps and the case
hope someone can help me out
On my FK-2001 that part is marked "6.00". But it has an "L1" legend and an coil symbol printed on the PC board, which means it's an inductor, not a capacitor. For that part to be burned there must be something downhill from it drawing too much current. Inductors don't just go bad like capactors sometimes do; they're just an insulated piece of wire wound into a coil. I would suspect the blue electrolytic cap next to it, or something else in that part of the circuit that gets its power through the inductor.

wanderhoden

08 Aug 2020, 09:37

@polecat
thanks for your help! L1 looks fine ..when you look on the pic what i made you see the blue electrolytic cap(c12)
than on the left they are 3 ceramic capacitor (c3 and c? the blue one hide it) c3 and the other one have a black dot or stripe on the top the 3. one is burnd black :D

User avatar
Polecat

08 Aug 2020, 19:51

wanderhoden wrote:
08 Aug 2020, 09:37
@polecat
thanks for your help! L1 looks fine ..when you look on the pic what i made you see the blue electrolytic cap(c12)
than on the left they are 3 ceramic capacitor (c3 and c? the blue one hide it) c3 and the other one have a black dot or stripe on the top the 3. one is burnd black :D
Mine is an FK-2001 so it's laid out slightly differently. L1 is "missing" (not used) on your PC board. The orange part below it is a crystal, denoted by "X1". And I believe that's what the "6.00" part on mine is, although it's not labeled as such. What does the legend say on your PC board for the burnt part? On my board there is a tantalum cap nearby, C12, which is 3.3uf 16V. That's a likely part to go bad, and might be what the burnt part is on yours.

I've got another early FK-2001 here that I can open up and check.

edit: I opened up an FK-3001 and the third capacitor (marked with an "A") on that one is labeled 0.1uF on the PC board under the edge of the plate <attached>. That's an unpolarized cap, monoceramic type, probably a 50 volt rating, although it's not labeled. There are several other identical caps on the FK-3001.
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wanderhoden

08 Aug 2020, 21:05

@Polecat thank you so much for helping me out and open all the keyboards :D

i bend the cap a bit away and now we can see the part name its c6
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Last edited by wanderhoden on 08 Aug 2020, 22:37, edited 1 time in total.

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Polecat

08 Aug 2020, 21:45

wanderhoden wrote:
08 Aug 2020, 21:05
@Polecat thank you so much for helping me out and open all the keyboards :D

i bend the cap a bit away und now we can see the part name its c6

IMG_5363.JPG
If it's a 0.1uF cap as I'm guessing it's probably connected across the 5 volt power and there would be several others at various spots on the board to reduce electrical noise. If that's the case try simply removing the cap or unsoldering one lead temporarily to see if the keyboard works normally. If it's part of the oscillator circuit or if there's another problem the keyboard won't work, but you won't hurt anything by trying that.

wanderhoden

08 Aug 2020, 21:52

oh ok i see but i have to bridge those two points than right?^^

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Polecat

08 Aug 2020, 21:55

wanderhoden wrote:
08 Aug 2020, 21:52
oh ok i see but i have to bridge those two points than right?^^
No! Don't do that or you'll short out the 5 volt power and that will do major damage. Just unsolder one lead and carefully bend the cap up and away from the PC board so it's no longer connected.

wanderhoden

08 Aug 2020, 22:27

iam not sure but i think that happend anyway couse the keyboard cable was also warm ;/

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Polecat

08 Aug 2020, 22:33

That could happen if the capacitor itself is shorted, and that seems likely seeing how it's burnt. Disconnecting the cap should allow the keyboard to work normally in that case as long as nothing else is damaged.

edit - that might sound contradictory, but a bad cap isn't necessarily a dead short, like you'd have if you connected the two pads together.
Last edited by Polecat on 08 Aug 2020, 22:35, edited 1 time in total.

wanderhoden

08 Aug 2020, 22:34

Polecat wrote:
08 Aug 2020, 21:55
wanderhoden wrote:
08 Aug 2020, 21:52
oh ok i see but i have to bridge those two points than right?^^
No! Don't do that or you'll short out the 5 volt power and that will do major damage. Just unsolder one lead and carefully bend the cap up and away from the PC board so it's no longer connected.

ah you are right both legs are on the same traid
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Polecat

08 Aug 2020, 22:39

wanderhoden wrote:
08 Aug 2020, 22:34

ah you are right both legs are on the same traid
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No, a capacitor wouldn't do anything if its legs are connected totether. The pads you circled will be the bottom legs of the two ceramic caps. The two pads below the circle will be the cap in question. But a bypass capacitor connects *across* power, not in line with it, so you never want to connect the pads together when troubleshooting.

wanderhoden

08 Aug 2020, 22:42

Polecat wrote:
08 Aug 2020, 22:39
wanderhoden wrote:
08 Aug 2020, 22:34

ah you are right both legs are on the same traid
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No, a capacitor wouldn't do anything if its legs are connected totether. The pads you circled will be the bottom legs of the two ceramic caps. The two pads below the circle will be the cap in question. But a bypass capacitor connects *across* power, not in line with it, so you never want to connect the pads together when troubleshooting.
uh ah ok now iam with you :D ih tought it must be a closed circle^^ :P

wanderhoden

08 Aug 2020, 23:03

wooohoo it works now
yeah you was right i was a bit of :D it was under the two i markd ....the cap have 104 on it
omg thank you soooo much !!!!
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Last edited by wanderhoden on 08 Aug 2020, 23:08, edited 1 time in total.

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Polecat

08 Aug 2020, 23:08

wanderhoden wrote:
08 Aug 2020, 23:03
wooohoo it works now
i was a bit of :D it was under the two i markd ....the cap have 104 on it
omg thank you soooo much !!!!
Nice, glad to hear that! 104 is the code for a 0.1uF cap, and the monoceramic type typically comes in a 50 volt rating. Not critical, those are there to suppress electrical noise and interference, but it's cheap and easy if you want to replace it.

wanderhoden

08 Aug 2020, 23:16

thank you so much for your knowledge (where did you get it from ?)iam new here and i rly want to learn more about it ...great stuff :D
and thanks for your time i rly appreciated it! sry for my broken english to ...
woohooo iam happy again

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Polecat

09 Aug 2020, 00:14

Well I've been using Alps keyboards for thirty years, and working with electronics for more than fifty years now. The best way to learn is by playing with things, and the information here is the best I've found. The Focus keyboards were made for many years and in many different versions, but the early blue Alps ones were probably the best of all. I'm using a modified blue Alps FK-2001 as my main keyboard:

viewtopic.php?f=62&t=22072&p=446271

wanderhoden

09 Aug 2020, 00:30

Polecat wrote:
09 Aug 2020, 00:14
Well I've been using Alps keyboards for thirty years, and working with electronics for more than fifty years now. The best way to learn is by playing with things, and the information here is the best I've found. The Focus keyboards were made for many years and in many different versions, but the early blue Alps ones were probably the best of all. I'm using a modified blue Alps FK-2001 as my main keyboard:

viewtopic.php?f=62&t=22072&p=446271
holy moly you have a black one? Oo :shock:
thanks again !
i work also a lot with electronics but iam from the arcade gaming corner ^^
1 question i still have the keyboard and the keys are awesome but the keycaps i rly dont like those there a so thin ...i mean my main keyboard was a gen1 model m looking 4 thiker keycaps ....do you have any suggsetions where i can find some nice ones ?

User avatar
Polecat

09 Aug 2020, 01:52

wanderhoden wrote:
09 Aug 2020, 00:30

holy moly you have a black one? Oo :shock:
thanks again !
i work also a lot with electronics but iam from the arcade gaming corner ^^
1 question i still have the keyboard and the keys are awesome but the keycaps i rly dont like those there a so thin ...i mean my main keyboard was a gen1 model m looking 4 thiker keycaps ....do you have any suggsetions where i can find some nice ones ?
I bought the black Focus brand new at a computer show back in the '90s. It was unusual even then, and I've only seen a few of them in all the years since. I finally got it where I wanted it, with an ansi-fied FK-2001 layout and double shot caps.

Sorry, I don't know of a source for new Focus keycaps as a set, especially for an ISO version. Almost every Alps keyboard uses a different layout, and new Alps keycap choices are very limited. To make matters worse, the stem positions on the Enter and Caps Lock keys aren't consistent between Alps keyboards. I've pieced together sets for several different Alps boards, mostly using Tai Hao sets as a starting point, but those aren't any thicker than the Focus caps. Perhaps someone else here has more info on this?

wanderhoden

11 Aug 2020, 23:30

hello again
the keyboard is still fine ...i orderd the part cant find one at home but iam sure i got those capacitors....
any way i noticed the keys on the keyboard have a loud ping sound almost like buckling springs...
found a video on youtube there is one the dude got the same keyboard and there was no ping sound what so ever :S
whats wrong with my board :/

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Polecat

12 Aug 2020, 02:58

There were several changes to Alps switches over the years, and then Focus switched to clones at some point. I'll bet someone here would trade you some tactile or linear Alps switches for your blues.

wanderhoden

12 Aug 2020, 14:13

Polecat wrote:
12 Aug 2020, 02:58
There were several changes to Alps switches over the years, and then Focus switched to clones at some point. I'll bet someone here would trade you some tactile or linear Alps switches for your blues.
the board is from 1988 i mean i'am not sure if they are blue alps but i think so ..
and i'am not sure but the cause of the pinging sound are not the switches it the metal plate :roll:

wanderhoden

12 Aug 2020, 23:28

here some pics from the inside
the switchplates are white ....i tought they are grey ?
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User avatar
Polecat

13 Aug 2020, 02:47

wanderhoden wrote:
12 Aug 2020, 23:28
here some pics from the inside
the switchplates are white ....i tought they are grey ?
Wiki says white after 1987, so that agrees with yours:

wiki/Alps_SKCL/SKCM_series

wanderhoden

14 Aug 2020, 20:09

just to finish this up ...got the capisator...all set and rdy
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but i still dont like the keycaps
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and here some fotos what i made
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