Vintage Audio
this section covers some restoration work that I did on my vintage HI-FI gear
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Article #1 | 06:28 PM Thursday 14/02/2019

SONY TC-K555ESA: Introduction

A Japanese (JDM) cassette deck. I think there was only one model above it: the TC-K555ESJ. But it is rare and expensive so I don't see myself having one of those pretty soon. But who knows? Anyway let's come back to the TC-K555ESA deck. This one has all the features you would dream of. To name a few: closed loop dual capstan, quartz locked linear torque brushless capstan motor, three heads (1 x S&F erase head, 2 x laser-amorphous record / playback heads), sapphire capstan bearings, ceramic cassette stabilizer, Dolby B, C, HX PRO, manual bias calibration, bias intensity selection, and other. Add a fully copper plated chassis and you're looking at a master recorder. At least this is what I consider mine to be. I don't have any deck better than this.

But even with all this high-tech inside, this machine is still prone to failures. Some bigger, some minor. Fortunately it is very repair-friendly. Boards are easy to get out and work on. TCM-200D10 mechanical block is a joy to operate and to fix -- bar the supply pinch roller alignment.

My deck was suffering a little bit so I decided to take a look at it.

Article #2 | 06:32 PM Thursday 14/02/2019

SONY TC-K555ESA: Technical Data

This cassette deck has the following technical characteristics.

TECHNICAL PARAMETERS
ParameterValue
Track System4 track 2 channel stereo system
Tape Transport MechanismTCM-200D10
Tape Speed4.8 cm/sec
Wow and Flutter<0.022% WRMS
<0.065% (DIN 45500)
Frequency Response15 Hz - 18,000 Hz (±3dB) - Fe2O3 tape
15 Hz - 20,000 Hz (±3dB) - CrO2 tape
15 Hz - 22,000 Hz (±3dB) - Metal tape
Distortion<1.3% (1,000 Hz / 0 VU) - Metal tape
Signal to Noise Ratio57 dB - Fe2O3 tape
59 dB - CrO2 tape
61dB - Metal tape
Heads1 x LaserAmorphous record head
1 x LaserAmorphous playback head
1 x sendust&ferrite erase head
Motors1 x direct-drive linear torque BSL motor for capstan drive
1 x DC motor for reel drive
1 x DC motor for mechanical operations
Power Voltage100 V at 60 Hz
Power Consumption24 W
Dimensions / Weight140 mm (H), 470 mm (W), 380 mm (D) / 13.6 kg

Article #3 | 06:33 PM Thursday 14/02/2019

SONY TC-K555ESA: Parts List

I have assembled a parts list for this cassette deck.

Descriptions and Parts Listings

The RECT(ifier) printed circuit board occupies the central compartment of the chassis and is located behind the mechanism block.

RECT P.C. Board (1-637-512-21)
IdentifierSchematicRecommendedMouser Number
C7063300 uF / 25 VTBD
C707220 uF / 25 VTBD
C708330 uF / 25 VTBD
C709220 uF / 50 VTBD
C7102.2 uF / 50 V BPTBD

The SYSCON printed circuit board occupies the left compartment of the chassis.

SYSCON P.C. Board (1-637-511-21)
IdentifierSchematicRecommendedMouser Number
C7513300 uF / 25 VTBD
C75210 uF / 50 VTBD
C753100 uF / 50 VTBD
C7544.7 uF / 50 VTBD
C755100 uF / 16 VTBD
C7564700 uF / 16 VTBD
C75710 uF / 50 VTBD
C759470 uF / 10 VTBD
C7601 uF / 50 V1 uF / 50 V FILMN/A
C7611000 uF / 6.3 VTBD
C7621 uF / 50 V1 uF / 50 V FILMN/A
C7631 uF / 50 V1 uF / 50 V FILMN/A
C764100 uF / 10 VTBD
C76510 uF / 50 VTBD
C766100 uF / 50 VTBD
C767100 uF / 10 VTBD
C80347 uF / 25 VTBD
C80410 uF / 50 VTBD
C805100 uF / 10 VTBD

The Playback printed circuit board is located in the upper right section of the chassis on top of the Record printed circuit board.

SYSCON P.C. Board (1-637-511-21)
IdentifierSchematicRecommendedMouser Number
C104100 uF / 63 VTBD
C10522 uF / 63 VTBD
C10622 uF / 63 VTBD
C1191 uF / 50 V1 uF / 50 V FILMN/A
C1231 uF / 50 V1 uF / 50 V FILMN/A
C12622 uF / 63 VTBD
C12722 uF / 63 VTBD
C1754.7 uF / 63 VTBD
C1764.7 uF / 63 VTBD
C204100 uF / 63 VTBD
C20522 uF / 63 VTBD
C20622 uF / 63 VTBD
C2191 uF / 50 V1 uF / 50 V FILMN/A
C2231 uF / 50 V1 uF / 50 V FILMN/A
C22622 uF / 63 VTBD
C22722 uF / 63 VTBD
C2754.7 uF / 63 VTBD
C2764.7 uF / 63 VTBD
C5014.7 uF / 50 VTBD
C5050.47 uF / 50 VTBD
C5064.7 uF / 50 VTBD
C5071000 uF / 63 VTBD
C509470 uF / 63 VTBD
C510100 uF / 50 VTBD
C5111000 uF / 63 VTBD
C513470 uF / 63 VTBD
C514100 uF / 50 VTBD

The Capstan printed circuit board is bolted to a steel plate that goes to the mechanism block on the back of the two flywheels. It implements the capstan motor driver circuit. There are two mandatory capacitor replacements on this board.

Capstan P.C. Board (1-620-086)
IdentifierSchematicRecommendedMouser Number
C90510 uF / 16 V10 uF / 16 V MLCC810-FK24X5R1C106K
C91110 uF / 16 V10 uF / 16 V MLCC810-FK24X5R1C106K

As always, let me throw a piece of advice. Do not hurry, take your time and do the job once. And do it well.

Article #4 | 06:56 PM Thursday 14/02/2019

SONY TC-K555ESA: Capstan Motor Board Restoration

Sony decks using the TCM-200Dxx mechanical block suffer from a dreadful capacitor leaking syndrome in various degrees on the linear torque direct-drive BSL capstan motor.

The issue doesn't really manifests itself until the leaking is severe and either the circuit tracks are severed or the the capacitors themselves short-circuit -- unlikely though. I have fixed at least three decks with the same problem.

However once the capacitors start leaking -- which they already did -- the electrolyte is attacking the solder compound. Removal of the capacitors will become close to impossible without the right tools. Let me tell you how I do it. I set the soldering station temperature at 290 degrees Celsius and I apply liquid flux on the surface mount terminals. Then I heat them up while applying some eutectic solder. It takes a little then I can easily remove the capacitors. Cleaning the pads however requires usage of more flux and eutectic solder. Then isopropyl alcohol to cleanup any traces of dirt left.

This is a precision job and if you don't have the right tools then disaster is guaranteed. You will most likely end up ripping the SMD parts off the copper traces. And this spells problems. A restoration is possible but the operation is very laborious. So I would avoid this procedure if I were in that situation.

Anyway let's continue.

This is the capstan motor printed circuit board. What I am looking at is the two SMD capacitors next to the supply capstan flywheel thruster shaft. They are rated 10 uF / 16 V.

Here are the old capacitors removed already.

And because technology evolved and we now have cheap MLCC high-capacity ceramic capacitors, I decided to give up on electrolytic capacitors in these positions. So I went with TDK MLCC miniature capacitors rated 10 uF / 16 V with X5R dielectric. So naturally very stable capacitors.

Clipping the leads to the right dimensions reveals that the SMD pads are perfect for soldering these SMT capacitors. Here they are mounted in happily waiting to do their job for decades to come.

But what are these two capacitors doing anyway? Let's examine the electrical schematics.

Both C905 and C911 are providing power supply rail filtering adjacent to the CX-20174 capstan motor control integrated circuit.

That's it for now.

Article #5 | 04:24 PM Saturday 16/02/2019

SONY TC-K555ESA: Better Capacitors

There are a few electrolytic capacitors in this deck that can be replaced with film counterparts for better reliability.

SYSCON Printed Circuit Board

On the SYSCON PCB there are three 1 uF / 50 V electrolytic capacitors around the supply rail regulators. They can be safely replaced with film capacitors of the same rating.

Replacements are in.

Old parts.

That's it for this circuit board.

Playback Printed Circuit Board

The playback printed circuit board is home to a few capacitors that can be improved for better reliability in time. I am talking about the electrolytic capacitors around the CD-20188 integrated circuits.

Notice how dirty the board in my unit is. The former owner used some kind of grease spray on it for some reason. I will clean it thoroughly using a spartan method. First I will apply ammonia based window cleaner on the entire board. Then let it work out for about five minutes or so. Then clean it with the shower and 40 degrees Celsius hot water. After that, the board goes to the kitchen oven for 10 minutes at 50 degrees. Sounds crazy but I have washed up a lot of boards like that. They all came clean and in good working condition.

Notice how clean the printed circuit board appears now. Original capacitors are designated C119, C123, C219, and C213 and are rated 1 uF / 50 V. Replacements are of type Panasonic ECQ series stacked film, rated the same as the old ones.

Old capacitors.

The other capacitors are all right for now. They don't require replacements. Neither these required. But I stated clear my reasons above.

If you will

Please note that all the work presented herein this site is non-commercial. This is my hobby and I am doing this in my spare time. Through this page I freely share my knowledge with you. But if you like my work, please consider helping me buy a transistor or a capacitor for my projects.

Thank you!

Copyright © 1998- Alexandru Groza