Vintage Audio
this section covers some restoration work that I did on my vintage HI-FI gear
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Article #1 | 07:36 PM Tuesday 28/01/2020

AKAI GX-95: Introduction

I bought this cassette deck about 10 years ago but I have used it only about 5 percent of the total time I dedicated to cassette listening. Why? Because I never liked how it sounded. I can hardly say this about any other decks that I previously had.

But is that bad? People on technical forums say it is. Some even swear by it. Some others are saying the reverse. I happened to be in both categories at the same time. Until I fixed the deck. Once I loaded a tape in its well and hit the play button, I was stunned. Mesmerized. I'm glad I didn't sell it because I had many occasions. Turns out it was a mechanical misalignment that was causing all the bad sound reproduction.

So here's me writing the first lines of this article about a deck that I considered worse than what people were talking on various forums out there. Even worse than some of the cheapest ones I had along the time. It was characterized by a very dull and boring sound. All that changed with the quick fix that I implemented. Well, it is not actually a fix per se but a part replacement by all means.

I always liked the electrical construction of this machine. Also, the mechanical block is of good quality. It was even shared by many other AKAI decks out there in a slightly altered form.

Let's go with the classical article approach then. Let's see the machine details and what I did to raise it back from the dead.

Article #2 | 08:15 PM Tuesday 28/01/2020

AKAI GX-95: Technical Data

This cassette deck has the following technical characteristics.

TECHNICAL PARAMETERS
ParameterValue
Track System4 track 2 channel stereo system
Tape Speed4.76 cm/sec ±1.0%
Wow and Flutter<0.028% WRMS
<0.04% (DIN 45500)
Frequency Response20 Hz - 19,000 Hz (±3dB) - Fe2O3 tape
20 Hz - 20,000 Hz (±3dB) - CrO2 tape
20 Hz - 21,000 Hz (±3dB) - Metal tape
Distortion<0.6% (1,000 Hz / 0 VU) - Metal tape
Signal to Noise RatioBetter than 59 dB - Metal tape
Heads1 x LC-OFC Super GX record head
1 x LC-OFC Super GX playback head
1 x ferrite erase head
Motors1 x FG servo DC motor for direct capstan drive
1 x DC motor for reel drive
1 x DC motor for mechanism operation
Power Voltage220 V, 240 V at 50/60 Hz
Dimensions / Weight154 mm (H), 460 mm (W), 350 mm (D) / 10.2 kg

Article #3 | 06:30 PM Saturday 15/02/2020

AKAI GX-95: Parts List

For the moment there is no need to replace parts in this cassette deck. But will keep this section here and will update it accordingly when the time will come.

Article #4 | 07:14 PM Saturday 15/02/2020

AKAI GX-95: Servicing the Mechanical Block

While electrically in very good working order, this deck had some nasty mechanical problems. Whatever cassette I tried, it was either skewing and ultimately destroying tape, or playing OKish but very dull. Even if I tried to adjust the azimuth. Turns out that the ceramic tape guidance armatures were broken and somebody repaired them with some kind of epoxy glue. Thus no matter how I tried to align the tape path, it was actually impossible. Furthermore, the nut that adjusts the supply side pinch roller axial position was bonded with the same epoxy.

This spells big trouble as the deck was totally useless, mechanics-wise. Thus I started a quest of hunting down a mechanical block from a dead or donor deck. Recently I managed to find what I was looking for but the price tag was a bit on the high side (about 80 E, shipping and handling included from Germany). Anyway, I'm happy that I finally found such mechanical block in good working condition. But as everything is relative, in this case, good working condition means that the tape path was intact and nobody messed up with the head alignment screws. However, the cam motor was totally broken. But there are a lot of small mechanical parts that can be salvaged. Take for instance the reel table motor which I used to fix the AKAI GX-F71 tape deck.

Anyway, I salvaged the entire sliding head block and two of the steel balls that the block slides on. In my deck, somebody lost two steel balls and the head block metallic plate could never be adjusted to be parallel to the mechanical block steel plate. That caused most of the head alignment problems. And also difficulties for the cam motor to operate the entire mechanism. I have also salvaged the pinch roller arms and the ceramic tape guide armatures. All of these have been transplanted onto my mechanical block.

Needless to say that I have dismantled everything and cleaned with either isopropyl alcohol (plastic parts) or acetone (metallic parts) and reapplied grease and Isoflex PDP 65 oil everywhere needed. I cleaned the flywheels of rubber residues. They were also dirty of some kind of unknown provenience yellowish greasy substance with a bad smell. Then I replaced the main transmission belt which powers the two capstans. Afterward, I installed the new cam belt and did the alignment as per the procedure described in the Service Manual.

Unfortunately, I took very few pictures because I was a bit overwhelmed by the amount of mechanical work involved in fixing this unit's issues. I'm not sure if I previously said it, but I'm not actually that comfortable working with mechanical assemblies. I'm more into electronics. But since I have no one to help me with the mechanical works, I had to learn everything on my own.

This is the mechanical block before servicing.

Viewing the mechanical block from above reveals the cam motor (leftmost side), the reel tables motor (center), and the direct drive capstan motor with the two flywheels (bottom side). The two trimmer resistors are used for electrical alignment of the cam motor operation.

Here are the two capstan flywheels already cleaned with acetone. There are some transparent friction washers that are easy to loose if you don't pay attention. The take-up capstan flywheel has magnets on both side: one side for the motor and the other side for the tachogenerator.

You can see here the take-up capstan motor tachogenerator PCB, the cam operations geared potentiometer, the reel tables DC motor, and the induction coils for the capstan motor itself.

Old belts are totally worn out. All of them have developed cracks and lost their elasticity. Because it was very brittle, I chipped the rubber of the idler tire when I removed it.

Now let's take a look at the parts that I replaced. Even though they are pretty much useless, I have mounted all of them on the donor mechanical block so that I won't loose them.

Head block plate and damaged tape guidance armatures.

Broken supply side tape guidance part.

Damaged take-up side tape guidance part.

Overview. The record and playback heads are in good condition. I will keep them in case I'll need it in the future.

View from underneath the supply side tape guidance armature.

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