momo

phew, sorry, summer hitted over here and now i am back with my misery with the cz... I soldered in the new board quite a while ago and gave it a try with some batteries. All LED's on for a short while, nothing on the screen and then nothing. Since then it was safely stored away and now i am trying to resurrect it once again...

I think I have to revive this thread ^^ Sadly I was in no luck with my repair attempts of the Casio CZ, however I got hold of a replacement PSU Board, for which I hope it turns out to be working... However whereas the board that was in the CZ is labeled with a "B" the board I have now is labeled with a "C". I suspect them to be different revisions and wonder if anyone knows if these are interchangeable?

Mhh, I'm still scratching my head - friend only gave me a short heads up that in his opinion the other transistors seemed fine. Following the instructions regarding +VBR adjustment on here: https://erichizdepski.wordpress.com/2020/07/18/casio-cz-1000-repair/?fbclid=IwAR3FNM15Vefreu2Rqln0iPo9PfgbT-dMov8y0s-ZbyHGbI7w2yOplK77Gg0 I tried to get t11 Emitter to 4.3V but to no avail, I can easily measure and track the voltages on t8 which is right before t11. Setting t8 to 4.3V makes t11 1.2V... It seems like I cannot go past 2.3V for t11. Furthermore I have problems to measure the variable resistance, it is bouncy and instead of going to max. 500k as proclaimed on the PCB it goes up to 1200k, thus maybe a broken trim pot?

I think you are right, just checked and it seems there are only 0.85V on the input of the JRC4558D, following back the schematic, this might be due to t11 emitter. I checked that transistor in diode mode! Whereas one leg seemed fine the other read none, I guess this points me to another defective transistor in there?! Will consult the friend later today!

At this point, it feels like I should've started a thread regarding my cz issues, instead of spamming this thread here ^^ I was able to figure out that the relai in there might be an issue regarding the output. Thus, according to another thread I tapped it at the 1k and 100k resistor to come along with the same weak output signal. Thus I went a step further and checked OPAMP 4558DD's in and outputs as this one provides both jacks with sound. The input of those is louder compared to their outputs, does this point me towards replacing the OA as it seems defective?

A Friend found the problem and it were two bad transistors! Now the cz will Power on again but new problems emerged as the line Output Is rather quite now (before all the issues it seemed almost too loud) and a static hiss - that seem to be affected by the Psu - with no real sound-Output on the headphone jack. any clues in any direction?

Sure thing! I havent run it on batteries in general, bought some in order to test if it may still run on those but it does not, so I took them out again

Hey @IanB, I measured the resistance from Red on the power board to the solder point in the star that is consisting of two pads being connected. Here again I get jumpy values, it does not stay constant at all jumping from mOhm->Ohm->kOhm I think Im most likely going to give this unit into repair to a technician, seems like I'm missing the skills to troubleshoot the cz...

Thanks for heads up @Brad Saucier! Hopefully this post will score me the remaining two points that are left ^^ Regarding the Diodes, as these are not obtainable any more, I have two 1N 4001 laying around I suppose these cannot be used as replacement for the DS135D? I am still restricted to two posts a day, but now I can still edit my old post ^^ @IanB, I measured the resistance from Red on the power board to the solder point in the star that is consisting of two pads being connected. Here again I get jumpy values, it does not stay constant at all jumping from mOhm->Ohm->kOhm Most of the time it stays in the kOhm realm!

Had to wait again for giving you this answer, and I think my current rank won't allow me to upload pictures on here... so here is a WeTransfer link for a file with the pictures in it. https://we.tl/t-pelDx2LdCf I retouched all solder points on the Power supply board as well as on the switching board, sadly without any luck... This makes me wonder if maybe the two ds135d diodes may be faulty. The don't look clean anymore, there are black sprinkles on the connectors (to be seen on a picture in the Wetransfer folder): Measuring them is pretty hard as well, on the solder side each measure with .1 ohm and if measured on the component side I get quite jumpy values.

Hey Ian, Just made the continuity test for BL<->R on the switchboard as well as the on the MA2M both cannot be read at a fixed value, it 'slowly' moves up and down from kOhm to mOhm and back. From looking at the schematics I would've expected 0 Ohms due to the direct connection without any resistors in place, is this assumption right? Regarding the Volts between BL and R it measures at 8.9V for both switch positions, ON and OFF Thanks btw for all your help already, feels like I'm securely learning new stuff

Finally...Had to wait 24h to make this post, seems like I am limited to 2 posts within a day. Thanks for the clarification, I opened the CZ up again and checked as you recommended. First I went with 'D' on the 40H000P. There I measured with PIN 6 and 7 (GND). The Volts do not change no matter if it is on or off and stays at around 3,67V. Same goes for measuring point 'E' on the same IC with pin 8 and 7. Went on and checked point 'F' on 74HC04, here I measured with pin 12 and 7 and got the same results as on 'D' and 'E', no changes with both switch positions. Voltage stays at around 3,6V. Thus I went on to check the Power Switch... Here I measured with GND of the DC input socket together with each of the 6 connections on the PSU-Board for Y-GND I got 0V for ON&OFF, R-GND has 8,9V for ON&OFF, BK-GND is at 0V for ON&OFF, BL-GND 0V ON&OFF, W had 8,9V for ON and 0 for OFF and BR seem to be a bit unstable for ON - somewhere between 1,6-2,1V and for OFF it stays at 1,6V I do not know which values are expected for the Power switch but these seem to off, don't they? I can measure 8.9V at the DC in Jack, so Power seem to come in.

The CD4011BPC did not resolve the issue, still no cz for me 😕 dont know if it is worth to try a BE?!

Alright, I am right with the assumption that the CD4011BE is a descendant of the CD4011B and thus can also be used? Will order that one chip and hope for the best... Would be shame if I cannot revive it Edit: Just checked and I have a CD4011BPC as a leftover this one should also work, shouldn't it?

Hey There, I hope I am lucky with reviving this thread... ^^ My beloved CZ-101 just died on me two days ago. It had a similar problem to the one described on here. If I turned the power off, all LED's and Sound went off and only the screen stayed on. I got the CZ like that, did not mind it too much and now it wont power on any longer... Sadly I am new to electronics, I do have a multimeter and do know how to check Volts and Resistances but the multiple voltages across the PSU-Board make it particularly hard to know where to measure what... I have to admit, my schematic reading skill are not that good I can see that 8.9V come in at the DC Jack, and I was able to realign emitter T11 back to 4.3V, sadly still nothing... Thus I remembered this thread and thought I might be good to just replace the IC that the OP had replaced in his procedure... Is there a way to test if my 4011 is still working without a oscilloscope? Do I risk anything by replacing it? Would it seem possible that a faulty 4011 could be the cause that my CZ wont power on at all?