Akai GX-255 Repair And Restoration
Almost every vintage unit needs to be disassembled for cleaning and to fix existing problems. This Akai GX-255 tape deck is no exception.
The tape path of this Akai GX-255 reel to reel is a mess and will need to be cleaned before any testing is done.
I had to manually turn the reels to get the tape off of the deck. The rewind torque of the motors could not overcome the sticky tape.
With the pinch roller removed from this Akai GX-255 open reel tape deck I can get it cleaned up.
Almost all vintage reel to reel repairs or restorations involve a lot of cleaning. Using cleaners made for tape units is the best thing to use.
After using some tape unit rubber cleaner the pinch roller from this Akai GX-255 is looking much better.
If you lay the Akai GX-255 on it's back it will be easier to clean the tape path. Look at that tape path! Has it ever been cleaned?
The entire tape path was a mess. When you have a mess like this you must clean it up before doing any testing.
This kind of mess will take awhile to clean up. Just keep cleaning until your Q-tips are perfectly clean.
I used Lasermedia CL-100 to clean the tape path during this Akai GX-255 repair and restoration. It's not an inexpensive cleaner but it works well.
As long as your Q-tip looks like the one shown in the picture below you keep cleaning. Once the Q-tip is clear then you are good to go.
Cleaning up the tape path when it's this dirty will take some time but this Akai GX-255 will never be able to perform well without it.
I've made good progress with getting the tape path cleaned up. I'll go over the tape path one more time to make sure that I've gotten everything.
I've got the tape path all cleaned up and it's about to do some bench testing of this Akai GX-255 reel to reel tape deck.
Once again always clean up the tape path of any tape unit before testing. Many times problems can be solved by just cleaning.
Another area that needs attention during any vintage stereo repair or restoration is the cleaning of the pots and switches.
In some units the pots and the switches are in a difficult position to get the deoxit straw into. The pots in this Akai GX-255 is one of those units.
You can bend the deoxit straw to help get the spray where you want it. I have collected various straws that I have bent in different shapes.
You want to get the deoxit into the pot and not all over the chassis. Deoxit is a great product but it can create a mess if you spray it everywhere.
I have removed the back cover of this Akai GX-255. This unit has a direct drive capstan assembly. No rubber capstan belt to worry about.
I found that either selecting forward or reverse play would not engage the reel motors. A defective bridge rectifier was causing the problem.
This defective bridge rectifier(D35) which is now removed supplies DC voltage to the reel motors and was causing fuse(F4) to blow.
I did not have a direct replacement available but I did have a bridge rectifier that would get this Akai GX-255 playing music again.
I had to do a little leg bending but the replacement bridge rectifier fit in nicely. Now this Akai GX-255 plays in both directions.
During further testing I found that there was an issue with very low audio on the right channel during playback.
This Akai GX-255 reel to reel tape deck has 2SC458 transistors. These are know troublemakers and need to be replaced.
I have removed the bottom panel so that I could access the artwork side of the assembly. Then I can remove the 2SC458 transistors.
I removed twelve 2SC458 transistors during this Akai GX-255 repair and restoration. I replaced these with SC1845 transistors.
Out of curiosity I tested all twelve of the 2SC458 transistors that I removed from this Akai GX-255 open reel tape deck.
The 2SC458 transistors that I tested were all over the place in respect to their gain(Hfe). Some were under 100Hfe some at 350+Hfe.
Six of the 2SC458's tested outside of spec. This Akai GX-255 would never be able to perform at it's best without these transistors being replaced.
After replacing the 2SC458 transistors both channels of this Akai GX-255 reel to reel are operating well.
The next step in this Akai GX-255 open reel tape deck repair and restoration is to clean up the control knobs and faceplate.
With the knobs removed you can get in the cracks and crevasses easier. Cleaning areas that probably haven't been cleaned in decades.
You may be surprised when you see how much dirt and grime comes off of most vintage stereo units.
This Akai GX-255 had something that spilled on the faceplate near the take up reel table that would not come off with normal cleaning.
On this Akai GX-255 you need to be careful what you use to clean the faceplate with. You can damage the surface if you are not careful.
During this Akai GX-255 repair and restoration I took a soft cloth and put some dish soap on it. I then rubbed the dish soap into the stain.
I then took a Q-tip and continued to rub the dish soap into the stain.
I then used both the cloth and the Q-tips as I continued rubbing on the stain.
It took some time but it started to look better. It's always better to not use a cleaning solvent to prevent any surface damage.
I got the stain removed from this Akai GX-255 reel to reel tape deck. It was worth the effort as this unit should operate for many more decades.
I'm about ready to get this Akai GX-255 back together and then I'll do some bench testing.
The record and playback functions work well. Fast forward and rewind are strong. This Akai GX-255 is now operating as it should.
This Akai GX-255 repair and restoration is complete, It's time for some music!