REPAIR GUIDE - TG-CD: Total capacitor replacement chart + useful info

[dead_man94]

can I use a standard polarized caps in place of the bipolar 10uf "c206 c205" ?

[ApolloBoy]

can I use a standard polarized caps in place of the bipolar 10uf "c206 c205" ?

No, you need to replace it with another bipolar cap.

[Fidde_se]

mg You can make a bipolar cap by using two polarized caps in series, but it will be half in value, so to make a 10uF you need two 20uF, put them plus to plus or minus to minus and they will become bipolar.

[NightWolve]

- CD-Rom grease dries up. (Regrease with white lithium grease)

Another good info/repair thread by Red Ghost I just noticed. The info about regreasing with white lithium grease was here all along, though it's lacking in specifics so I might as well add a link with more details and where it solved a user's problem, mine too with my Turbo Duo.

To do this proper, I recommend removing the driving motor (you can then hold it vertically and drop motor oil in it). It has two precision screws that are glued tight so it might be hard to break said screws free, but if you can do that and lift out the motor -- thereby removing that swirly sprocket from the rest of the circular sprockets/gears -- the laser unit will then be free to easily slide back'n'forth on its poles all the way with no problem. This will allow you to effectively/easily clean off the old grease and apply/spread the new, fresh grease (white lithium, as recommended). Being able to move the laser unit back'n'forth will help make sure plenty of new grease gets inside the plastic tubing that it slides on.

So what does this solve ?? It solves the problem of an audio track cutting out (AKA skipping). When a read failure occurs of the subcode data on an audio sector, the laser unit does not skip on to the next readable sector, it just ceases to read any more audio sectors, so the music simply stops, the game continues on and only when you trigger another loading of a track (for example, you exit a town, or you advance to the next stage in the game and it's time for the background music to change), then and only then will the music resume, until the next read failure of course.

This simple problem, 20 year-old dried-up grease, can mislead people into thinking that the whole laser unit itself is dying and needs to be replaced or that certain potentiometers related to it might need to be adjusted... You might even blame the use of a CD-R as I momentarily did before testing factory pressed NEC and music CDs only for the problem to continue to manifest itself. Point is, don't rush to judge the problem as being more severe than what it might actually be!! This is a cheap and helpful solution that most can do themselves rather than shipping (which can cause further damage) a CD-based system off to somebody else!

mg You can make a bipolar cap by using two polarized caps in series, but it will be half in value, so to make a 10uF you need two 20uF, put them plus to plus or minus to minus and they will become bipolar.

I know that connecting capacitors in parallel or in series is to affect capacitance value, which will either double it or divide it, but I had not heard this... You can order non-polarized (AKA bipolar) ceramic caps (meant for AC circuits) at 10 uF just fine and they'll likely be pretty accurate as far as their stated value (the 10uF caps I bought from Digikey were about 9.5 uF when measured with my DMM, but the 100 uF caps were way too low, like 60-70 uF - ceramic caps tend to be a lot lower than the stated value I noticed, so just FYI).

As to why NEC intentionally used 2 non-polarized [ceramic] capacitors there, it could be that there was DC to AC conversion for something, but most likely power inversion producing higher voltages and that ceramic caps handle "ripple" well (refer to steve's post for details). Other than that, I dunno, but yeah, I'd replace them with the same type unless someone like thesteve could explain more...

EDIT: I guess this idea is somehow safe to do:

http://electronics.stackexchange.com/questions/21928/can-you-make-a-non-polar-electrolytic-capacitor-out-of-two-regular-electrolytic

If two, same-value, aluminum electrolytic capacitors are connected in series, back-to-back with the positive terminals or the negative terminals connected, the resulting single capacitor is a non-polar capacitor with half the capacitance.

The two capacitors rectify the applied voltage and act as if they had been bypassed by diodes.

When voltage is applied, the correct-polarity capacitor gets the full voltage.

In non-polar aluminum electrolytic capacitors and motor-start aluminum electrolytic capacitors a second anode foil substitutes for the cathode foil to achieve a non-polar capacitor in a single case.

Not sure I trust this idea all the same. Steve ?? Well, I found at least one negative consequence: the Equivalent Series Resistance (ESR) of the paired capacitors in series will be doubled (note: aluminum electrolytic caps have higher ESR ratings than other types), so that's not good... Anyhow, he does appear to be correct, you could do this with 2 capacitors that are twice the value of what you want. If you solder the (+) leads of both capacitors together, then the two other (-) leads, when connected to the PCB, would behave as a non-polarized cap...

I would agree with what somebody said at that linked website above:

In general, this sort of trick should be considered a last resort. Since bipolar capacitors are usually needed for signals, it can often be arranged to require a lower bipolar capacitance. Multi-layer ceramic caps have advanced significantly in the last decade. If you can make do with 10 uF instead of 100s of uF, a ceramic can can probably do the job.

OK, and this is from Wikipedia:

Series connection is also sometimes used to adapt polarized electrolytic capacitors for bipolar AC use. Two polarized electrolytic capacitors are connected back to back to form a bipolar capacitor with half the capacitance.[citation needed] The anode film can only withstand a small reverse voltage however.[18] This arrangement can lead to premature failure as the anode film is broken down during the reverse-conduction phase and partially rebuilt during the forward phase.

[Fidde_se]

Yeah it's an old capacitor trick used for audio back in the day, SMD/SMT today are made out of ceramic and porcelain inside, and what usually sounds best is polypropylene and a few other plastics (different plastics combined is actually best) but plastic was not invented until the 60's so then there was only paper in oil and other electrolytic capacitors, and heres the why, when plastic capacitors were discovered they were high in price and and relatively low in value, and here's the real deal, audio is AC, the signal goes up (plus), threw zero, and down on the minus, and then it had to be non polarized otherwise only half the sinewave would come threw, well in theory... as it will try to come threw on the other half but deformed creating huge amounts of distortion, so thats why this was pretty common back in the day, it was just impossible to find a ceramic/plastic 100uF capacitors for line filters in loudspeakers... nearly all old loudspeakers had bipolar electrolytic caps, the danish capacitors company Jensen was enormously famous for them, but sounded like crap compared to when plastics came around.

[Fidde_se]

Should also note that don't trust your DMMs to death, there are several ways of measuring capacitors depending of what they are for and their specs, they send out a voltage for testing and some use high or low voltage, it also sends it out on different frequencies, standard is 1Khz, expensive capacitor meters have tons of different settings, sometimes even expensive testing equipment show the wrong value even if the components value it's actually spot on, it's a whole world of know how just to know how to measure components correctly.

It's as confusing as for trying to explain to non electrical people that electrical outlets just gives 110v at 60hz, and that it gives other voltages at other frequencies (yes not intended), a little voltage at every half or double the frequency, or triple for that matter, and that bad sinus deformed voltages can be found all over the spectra, it could contain a gazillion voltage with 1mA at 1Ghz, yeah line filters are needed.

[NightWolve]

Yeah, it's definitely an interesting trick, I didn't know anything about it. At first I didn't believe it. As for my DMM, I'm very happy with the VC99. The 4 ceramic 100 uF capacitors that I bought which failed to operate properly were measured at ~60 uF, so there was definitely a problem with them (the actual device no longer functioned properly). A waste of good money at DigiKey and I had to go back to electrolytic anyway... The 10 uF ones measured at ~9.X uF, so I kept using those, but I definitely lost some trust with high value ceramics. I will always make sure to measure a capacitor before using it to see how close it is to the stated value. I wasted a few hours trying to figure out the problem with those bad ceramics, so I prefer not to go through something like that again if possible.

[dead_man94]

just got done recapping my pc engine cd rom, and wanted to make a note that I had (5) 4.7uf 16v caps, instead of the 25v listed.
might help someone thats replacing them and thinking they have to find 25v caps.

thanks Red Ghost "for this cap guide" and chop5 "for what pots need adjustment" almost thought i had a dead laser, but end up being dead caps.

[NightWolve]

16 V is OK/safe. The circuit board generally operates at ~5 Volts DC after the power regulator, so capacitors that are rated 10 V or above are safe. But the bigger they are, the better they are: they last longer, handle "ripple" better and sometimes there is power inverting going on so they need to be of higher voltage in that area of the board. This comes at the expense of size and $$$: a 25 V cap is physically bigger and more expensive than a 16 V cap, etc. Anyhow, I was confused about this as well when I got started, but there ya go. When replacing a capacitor, you simply need to match the capacitance value exactly, but the max breakdown voltage can be equal or higher (and higher/bigger is better/safer).

[dead_man94]

16 V is OK/safe. The circuit board generally operates at ~5 Volts DC after the power regulator, so capacitors that are rated 10 V or above are safe. But the bigger they are, the better they are: they last longer, handle "ripple" better and sometimes there is power inverting going on so they need to be of higher voltage in that area of the board. This comes at the expense of size and $$$: a 25 V cap is physically bigger and more expensive than a 16 V cap, etc. Anyhow, I was confused about this as well when I got started, but there ya go. When replacing a capacitor, you simply need to match the capacitance value exactly, but the max breakdown voltage can be equal or higher (and higher/bigger is better/safer).

yeah i understand that higher voltage caps can be used, but was just putting out there that mine were 16v and you dont have to use big ol' 25v;p but thanx for putting up some good info!

[TurboHuC6280]

Believe it or not, my TG16 CD drive came stock with a KSS-220A.  I was completely expecting it to contain a 162A, since this seems to be the norm.  Has anyone else observed this?

[Keith Courage]

Yes, a good deal of slightly newer drives have 220A in them. Unfortunately, for some reason I have encountered more bad 220A lenses over the years than older the style 162a lens.

[TurboHuC6280]

Yes, a good deal of slightly newer drives have 220A in them. Unfortunately, for some reason I have encountered more bad 220A lenses over the years than older the style 162a lens.

I've got a few spare Discmans with lasers of both types, so hopefully that is at least some insurance for the future. 

My 220A-based drive was in beautiful shape when I opened it up.  A little bit of white grease and now it sounds / runs like new.

[POPNDOUGH]

Thanks for this Platinumfungi. It helped alot when I replaced the caps in my CD player, but now I think my CD Dock might need new caps as well.

Is there a guide that shows how to open up the CD Dock to even get to the PCBs?
It only has like 2 screws, then a bunch of weird fasteners that I'm not sure what to do with, and 2 tabs on the side of the CD mounting part that don't really want to let go. I'm afraid to force it because I don't want to break anything.

Anybody disassemble the CD Dock before?

[Keith Courage]

There are 3 4.5mm security screws you need to remove just under where the CD drive goes. Also, unscrew the two philips screws near by. All the front screws can be left alone under where the TG16 itself sits. After removing the screws simply pry slightly on the two tabs you mentioned to release the base.

[mario_pic]

wondering if any one has a kss-220a assembly im looking for all of if i got a bad laser and a droped spindle motor  looking to replace both and use the newer style spindle motor cd clamp  vs the old magnetic one

[thesteve]

you should be able to find the KSS-225A which also works

[thx1138]

I've been in the slow but steady process of compiling repair/useful information for our poor friend the TG-CD for awhile now. If you have anything you want to add just let me know 

Just wanting to check this for the CD-rom2 as well, the Japanese version ?

[BlueBMW]

Only difference I know of is that the Japanese unit doesn't have a ground wire to the bottom shell piece

[wilykat]

Only difference I know of is that the Japanese unit doesn't have a ground wire to the bottom shell piece

Also, Japanese version doesn't come in black

[Keith Courage]