Korg Forums

simianquade · Joined: 02 Jun 2016 Posts: 11

Hello,

I have been having problems with my Korg M1. Volume kept cutting in and out. I have removed the power supply P.C.B an can see there are capacitors that have leaked. A common problem I would suspect in an older piece of hardware.
I am having trouble purchasing capacitor C1 from the board as I am not yet able to determine the specifications/information printed on its side.
C1 being one of the large dark pink rectangular type.

Please if possible, could somebody describe the symbols representations so that I can identify the meanings of numerical value or point me towards a site that does this.

Or send towards to a U.K outlet that sells this specific type with what to ask for ?

Thanks

voip · Platinum Member Joined: 27 Nov 2014 Posts: 3773

Are you sure it is capacitor leakage that you're seeing? The larger electrolytic capacitors on the PSU board have had glue poured around their bases to stop them vibrating during movement of the keyboard, and this can give the appearance of leakage.

It might be worth measuring the voltages on the power supply outputs, with the supply connected to the rest of the electronics in the M1.

There are several versions of the M1 PSU, geared for different markets e.g. USA, Japan, Europe, and the part numbers differ. Which version do you have? KLM1267, KLM1268, KLM1269.

.

simianquade · Joined: 02 Jun 2016 Posts: 11

Hi

Thanks for the reply.

I have the KLM-1269. I have already removed the larger capacitors so I won't be able to test the voltage in circuit at this point without more complication.
I am hoping that what I was seeing was leakage as there was the substance oozing midway down the sides.
I have already purchased the other larger fixed cylindrical capacitors needed but can't access the problem with the large red/pink ones described earlier.

I am aware that this P.C.B isn't in manufacture any more too.

Thanks again

T3owner · Senior Member Joined: 17 Jun 2011 Posts: 368 Location: USA

As shown in the KLM-1269 schematic in this thread...
http://www.vintagesynth.com/forum/viewtopic.php?f=5&t=53799
...C3 is one of the capacitors used in the AC line filter. It's specially rated for such usage. It isn't an electrolytic type. Why do you think it needs to be replaced?
_________________
Korg: T3EX, 05R/W | Yamaha: Motif XF6 and XS6, A3000V2, A4000, YS200 | Fender Chroma Polaris | Roland U-220 | Etc.

voip · Platinum Member Joined: 27 Nov 2014 Posts: 3773

I agree with T3owner. Electrolytics can fail by leakage, with some makes worse than others, but polyester types used for mains filtering do not have this problem and are self-healing.

simianquade · Joined: 02 Jun 2016 Posts: 11

Hi
I could see that there was a substance coming from the side so I have since removed and disposed of those that were so. I just need to fill the empty space that I have created.
To be honest I first assumed the problem could be to do with the head phone jack out put as that was how I was listening. I knew it wasn't the battery because the symptoms of that failing last time was that the only sound hearable was white noise, if that's the correct terminology. So admittedly before I had reached the jack after having had opened it up I noticed the mains pcb had capacitor leakages.....so I removed the capacitors seen to be at fault.
Although I suspected the jack I still thought that it was something to do with the flow of power. The reason behind that was because as from the point the instrument was turned on it would play the deeper layered sub base sounds and chords ect but would slowly start cutting out when over loaded with key touches. I could play single keys simultaneously all night ........Which a little frustrating.

voip · Platinum Member Joined: 27 Nov 2014 Posts: 3773

There's no harm in giving the headphone jack a cleanout, using a switch cleaner/lubricant like Servisol 10, or Deoxit. Contact oxidation occurs in most synths to some extent, even the flagship Kronos (although the Kronos 2 comes with gold plated contacts).

.

simianquade · Joined: 02 Jun 2016 Posts: 11

So I still would need an answer as to where I can purchase the correct electrolyte and/or its given properties in circuit board such as this?

https://picasaweb.google.com/102517198029908672164/6296017909412256257#6296017910509205714

voip · Platinum Member Joined: 27 Nov 2014 Posts: 3773

If it is the capacitor in the centre of the image that you wish to replace, it is not an electrolyic, but most likely to be a foil capacitor with polyester dielectric, and it serves as part of the mains input filtering, serving to attenuate the interference trying to get in, but also preventing interference from the Korg from getting out. There is nothing to leak out of this type of capacitor. If you feel you must replace it, go for a 0.47uF 250V a.c. Y-type capacitor. These capacitors are designed for continuous service at mains voltages. Most of the markings on the capacitor are related to the various approvals bodies that the capacitor type has been tested by, typically UL (Underwriters Laboratories) recognized and IEC 60384-1 compliant.

.

T3owner · Senior Member Joined: 17 Jun 2011 Posts: 368 Location: USA

simianquade · Joined: 02 Jun 2016 Posts: 11

I appreciate all your feedback. It is all very helpful. I no longer have the missing components so I will replace them as advised. I could see that the fuse would blow now if the power was over loading via fault ...that's why its there that now makes a total of logical sense. I did just assume the interference was coming from the start of the circuit upon seeing the assumed leakage but without testing the circuit first there was no real concrete evidence of abnormality. And yes that is c1 that is missing thanks

simianquade · Joined: 02 Jun 2016 Posts: 11

Hi.....So as you can see within the photo I sent of my existing P.C.B there are missing components (C1) Electrolyte 0.47uF 250V a.c. Y-type capacitor. I have searched for 0.47uF 250V a.c. Y-type capacitor on the internet and bought. When they arrived they were about the size of my small finger nail and no where near the pre-existing components (more the size of c3). I could see that this could have been the case before I asked and bought them but they were only cheap so I didn't break the bank. My question is where do I buy an equivalent? They most definitely have the same rating's but are different in size....

the_crimson_thunder · Posted: Thu Jul 07, 2016 1:59 pm Post subject:

Hi,
here's an example of one that fits definitely:
http://www.reichelt.de/Funkentstoerkondensatoren/PAN-X2-470N/3/index.html?&ACTION=3&LA=2&ARTICLE=129277&GROUPID=3157&artnr=PAN-X2-470N

Take a look at the attached picture:

There are several holes on the pcb to where you can solder the capacitor (marked with red circles). You have to measure the spacing between one of the two on the left side and one (of three) on the right side. That is the spacing the 'legs' of the capacitor should have to fit. The example I've mentioned above has a spacing of 22.5 mm and therefore definitely fits... Very Happy

BTW: I strongly recommend to replace its 'brother' too - so just order two of them and you're safe... Wink

T3owner · Senior Member Joined: 17 Jun 2011 Posts: 368 Location: USA

simianquade · Joined: 02 Jun 2016 Posts: 11

So it's not an electrolyte or a y-type but it is an X2....Well that put's me back to exactly where I was when I first asked.

Well I have gotten this information....The ECU is a Panasonic part number. These can be obtained through R.S Counter. Stock code 622-5069. Voltage is said to be higher but they are in accordance to the P.C.B. Lead pitch 22.5 mm.

Check it out for yourself

http://uk.rs-online.com/web/p/polyester-film-capacitors/6225069/?searchTerm=622-5069&relevancy-data=636F3D3126696E3D4931384E525353746F636B4E756D6265724D504E266C753D656E266D6D3D6D61746368616C6C26706D3D5E283F69292852537C5253207C52532D293F5C647B337D285C73293F5B5C732D2F255C2E2C5D285C73293F5C647B332C347D2426706F3D313426736E3D592673743D52535F53544F434B5F4E554D4245522677633D4E4F4E45267573743D3632322D35303639267374613D3632323530363926