Philips CD 204, need full recapping ?


2019-02-06 8:08 pm
I recently got a Philips CD 204 off a flea market and it is indeed working.

It has problems with the tray, one of the gear (made with the infamous Philips orange plastic) has all of it teeth shaved off and the belt is worn, but I have ordered replacements for both.

On first test there was minor distortion on the RCA output and severe distortion on the headphone output. Replacing two axial blue Philips 15 uF capacitors fixed both problems and it now sounds good.

My problem is that the boards are full of those blue axial Philips Capacitors and I guess many are now quite out of specs. Is it worth a full recapping ?
My concern is that the boards are 35 years old and unsoldering an resoldering several caps might cause more harm than good. The power supply uses higher quality Nichicon caps and I hope they are in far better shape than the blue Philips.

Any suggestion ? should I keep it as it is until it is running fine or should I replace all blue caps ?



2019-02-06 8:08 pm
I did a quick check with Farnell, and replacing all caps in the cd player is quite expensive. Replacing only the blue axial philips is more reasonable; I selected new axial capacitors and they are available only from Vishay. I might look for standard radial capacitors, but that would spoil the "look" of the boards

The laser preamp board underneath the CDM-1 has five axial caps which should be replaced, but the schematics of that board is not present in the service manual. Is it mean to be serviceable or is it an integral part of the CDM-1? I'm quite afraid to detach laser and PD's cables from the board ...

Anyone has any experience recapping a CD 204 or CD 104 (pretty similar) ?
I have a Magnavox FD2040 version. I got it to replace the CDM-1 in my Revox B225 but I ended up getting a 'NOS' CDM-1 transport whilst waiting for it to be delivered. It was advertised as needing a push on the tray to get it closed (and a pull to get it fully open) but otherwise plays CDs. And sure enough that's accurate, it plays even though it got dinged on the way to me and the front fascia was coming away. I've dismantled the tray and it doesn't seem to be either the gear or the belt, it's the actually slidling mechanism that is 'stiff' in the middle. I can't work out what it is exactly, I've sanded down the surfaces that the rollers roll on , and it's very slightly better (in my book, not making things worse is always good). Does anyone have any suggestions please?

I'm quite happy having it as a spare CDM1 but I already have a lampizated Revox B225 and a lampizated Luxman CD player, so this one has little chance of getting into the rotation. But it'd be nice to just get it fixed up as much as I can.


2019-02-06 8:08 pm
I did fully recap my CD 204 (including the CDM-1 control board) and it is working fine, it is very quick to read CD's and plays basically everything.

Regarding the loading tray, it use pegs on the side and the top sliding inside slotted guide (which actually mostly control the mechanism in the tray itself to raise/lower the disc on the CDM-1) and two grooved rollers pushing on the sides of the tray. The whole mechanism relays in the external shell of the tray assembly being in perfect shape, if it received shock, something might be out of alignment and the tray sticks in the middle.

Honestly it is very noisy and over-engineered, but all early CD players are over-engineered.
I did a quick check with Farnell, and replacing all caps in the cd player is quite expensive. Replacing only the blue axial philips is more reasonable; I selected new axial capacitors and they are available only from Vishay.
Anyone has any experience recapping a CD 204 or CD 104 (pretty similar) ?
Over the years I’ve replaced thousands of electrolytic capacitors in all sorts of audio & video gear. I live in the states and get most of my replacement capacitors from Digi-Key or Mouser. Occasionally I use Element-14 or some of the audiophile specialty parts distributors who sell on eBay.

I don’t find high quality electrolytics to be terribly expensive. It is best to purchase in multiples of 10, 25,or 100 pieces of any given value to get a lower price. Single-piece prices can be rather high. For extremely common values (like 10uF, 47uF, 100uF at 16V or 25V) I often buy 100 at a time. That keeps the cost <$1 USD per capacitor. Sometimes I can get 10 pieces per $1 USD.

I rarely use axial lead capacitors. There isn’t a wide enough choice of brands & specs in axial.

The most important capacitors to replace in old Philips CD players are the 33uF or 47uF axial units which often have blue sleeves. Note: It is perfectly OK to replace a 33uF with a 47uF. I’ve done this so often (successfully) that I don’t keep very many 33uF capacitors on hand any more.

The following two tests will identify faulty electrolytics:
  • 1) ESD. Equivalent Series Resistance. Old capacitors dry out. This causes ESD to rise. In the worst case the capacitor becomes an open circuit. For 33uF or 47uF the ESD should be <5 ohms. Because ESD meters vary in performance I often compare the measured ESD of a brand new capacitor to the old one. If the old capacitor ESD is more than 2x-3x higher than a new capacitor then I replace it.
  • 2) uF. This doesn’t often change. The uF tolerances for electrolytics are wide. +/-20% is about the tightest. Often the spec is -25%/+100%. In other words it’s OK to have more uF in most applications.
A cheap easy-to-get device which measures both ESD and uF is known as the “$20 transistor tester” or “GM328.” I strongly recommend having one on your worbench. Many details can be found at EEVblog. It measures many other types of electronic components also. Basically it is “must have” bench tool for vintage audio repair/restoration.

As for the service manual details, Philips published sub-manuals for their CDM1 & CDM2 transport assemblies. I do believe these can be found on-line for download. I am lucky to have many Philips service manuals covering the 1980 to 2000 era because I operated an audio/video repair shop back then. If/when I find some spare moments I intend to make high resolution scans of them.



2019-02-06 8:08 pm
I honestly tend to do very few recapping on vintage electronics, in many cases it is unnecessary and it only damages the electronic board. There are known series of caps that needs to be replaced regardless and the blue axial Philips are among those. I have yet to encounter a blue axial cap that as of today it is working ok, they all fail to variable degrees. I think Philips itself knew those caps were crap and relegated their use to less critical functions (smoothing capacitor mainly): in PSU Philips used high quality Rubycon caps which in 99% of cases are still good today; in the audio section Philips would often use good quality Elna (which again typically are still fine with some notable exceptions, as the Duorex II).

The CD204 is an exception to the latter rule as blue axial capacitors were also used for the output decoupling stage. I have replaced all caps in the CD204, but, as I suspected, only blue philips caps were to be replaced. other caps are still fine. I chose aesthetic over performance and opted for the only axial caps you can find today, Vishay. I think they are good capacitors (Farnell does not sell chinese low quality caps) but very likely audio gear is not they typical field of application. Anyway fitting radial caps in place of axial is not very nice to the eye, it is fine if they are just a couple, but this older CD player have 40+ axial caps.

I waited to recap the CDM-1 control board as I was afraid to break the delicate hybrid circuit or the ribbon cables. But few months ago the CD204 stopped reading any CD's so i took the courage and recapped the CDM-1. Luckily nothing got damaged in the process, and the player is now happy again. I guess CDM-1 uses a similar circuity as CDM-4/19 where a blue axial cap is used to smooth the laser diode current: if the cap fails, the laser does not turn on properly and the player does not work. It is a common failure in all CDM-4 based players.
Are these Siemens (ROE) tantalum capacitors any good for recapping the CDM-1? B45178-A3336-M 33uF/16V


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2019-02-06 8:08 pm
Not a big fan of tantalum, when they fail, they fail spectacularly to a short (often with a pop). I do not like them near delicate electronics as in the CDM-1.

One way to reduce the risk is de-rating their voltage, i.e if the electrolytic caps was 16 V, use a 25 V tantalum. But honestly I would not use old stock tantalum, even if they measure fine.
I rarely use tantalum capacitors.

Tantalums were popular during the time period from the 1970-2005, especially in test equipment & other premium-grade gear.

But after 2005 both electrolytics & metallized film capacitors were improved considerably in performance & life expectancy by the major manufacturers.

For uF values up to 10uF I often use metallized film (polyester or polypropylene) when available space on the PC board allows it. These capacitors have excellent performance & will last almost forever.

Above 10uF I use high-quality electrolytics made by well-known brands such as Panasonic or Nichicon.

For applications in power supply filters I make sure to select electrolytics with very low ESR & a high enough “ripple current” rating.

For audio coupling capacitors where there is no DC voltage across the capacitor I select “bipolar” (non-polarized) electrolytics. To me these sound better.

I rarely use high priced (>$10 USD each) “audio boutique” capacitors. I prefer to use the major name brands. Companies like Nichicon offer specialized electrolytic capacitors for audio applications. These cost a bit more but are still very affordable. I do use them.

I rarely replace every capacitor in a given piece of gear except when the item is an antique or vintage tube (valve) radio or amplifier. In newer items (mostly solid-state) I do test every electrolytic for ESR & uF. When both parameters are in-spec I leave the original capacitor in place.

In Philips CD players the small blue axial-lead electrolytics of 33uF or 47uF are notorious for gradually failing with high ESR. But it is rarely necessary to replace every electrolytic on the PC board.