AKAI GX Reel 2 Reel REV PLAY Channel Dead?

[herbman1975]

Howdy everybody!

I recently picked up an Akai GX-280D-SS Quad deck. It had some bugs, but after a good cleaning, lube, and warming up before use, it has proved to be a pretty good unit.

Anyhow, the forward play function works fine, but when I use the reverse play feature, I get output from the left channel only. I can flip the tape, and the same material plays in stereo in forward play.

I just don't understand how the head could work in one direction and not the other.

I really appreciate anyone who takes the time to post some help! Many thanks in advance!

:smoke: herbs

[Orcinus]

Because it either uses a different head, or different channels on the same head. Check your wiring from the heads, make sure there isn't a short or broken wire.

[inductor]

is the record\play switch dirty-contacts

[herbman1975]

So, wiring or dirty contacts? I guess I need to De-Oxit the hell out it...

The channel that is dead is the rear right. I flipped it to quad and all the needles jumped except that one.

I guess I could live with it. The deck played in forward play in stereo. It just won't auto reverse or play in quad. It is bare bones forward play, then take off the reel and flip it.

I want all the features :dammit:

[cableguy2]

Well, the 280 model unfortunately used the Sanyo LD-3141 amp in the playback and record. I have a 1730d that uses the same bad little chip. I finally found some extra boards that were good and it works okay now. I have a couple of replacements for the LD-3141 lying around as well.

If it doesn't run backwards, thats got to be in the logic somewhere doesn't it. Good luck.

[cableguy2]

These 4-head, 3-motor models are about 100% alike and can be regarded as the predecessors of the GX-270D-SS. They are relay controlled and can do a single auto-reverse cycles during playback in 4 track, 2-channel mode only.
In 4-channel mode the user has the ability to use auto-repeat, which means the machine goes into REW mode at the end of the tape as soon as a piece of sensing foil reaches the reverse sensing post. At the beginning of the tape when the other sensing foil reaches the second sensing post again the machine stops and goes into playback mode again. When auto-reverse and auto-repeat aren't used there's also an auto shut off function which cuts down the power.
Just like the 2-channel models GX-280/D and GX-285D, the servo control takes places with an external "head" which is mounted on the capstan motor. This head "checks" the motor revolutions. The 280D-SS does not have the GX heads. The solenoid which pulls down the playback head a little when the deck switches to reverse mode is not present in these sets since they already have a 4-channel playback head.
The differences between the GX-280D-SS and the GX-297D-SS are just internal. Except for the headcover they are 100% identical externally. The GX-280D-SS has the fourth edition of the KD-1001A system control board, the GX-297D-SS has the fifth edition.
The GX-280D-SS uses the E4-200 and E4-250 erase heads, the GX-297D-SS uses the E4-210 and the E4-260 erase heads.

some info on that deck.

[blooeyz]

hi all; If its like a GX280d Akai i once head....and reverse isnt quite right..it had three heads, the third head....moves over slightly to allow reverse play., slides up and down, .sometimes it doesnt slight over quite enough..remove the head cover and gently lift or push on the third head... with headphones on..see if that helps...mine wouldnt play in reverse well till i adjusted the tiny screw next to the third head....which limits the distance the head can lift up or be pulled down by the solenoid....
hope this is helpful...
oh, the GX210, GX215, GX220 and 225 have the same head setup....from the Akai GX230d onward they used four non moving heads...
blooeyz

[herbman1975]

I still haven't taken this thing in for service. The REV play right channel is still messed up, and it will only play in either direction on sporatic occasions. It will half-ass work one day and not the next.

Time to take it to the old man...

:smoke: herbs

[jayboy]

It's been a long time since this thread was posted, but the answer to the problem is probably in the REVERSE relay that is located on the switch board that holds the STEREO SELECT and MONITOR switches (there's only one relay there. The normally open contacts are probably only mating intermittently and need to be burnished or cleaned.

The GX-280DSS uses a 4-channel playback head. In 2 channel stereo FWD play, only two of the four channels on the tape are played through the FRONT L and R playback audio amplifiers. The other two channels (the 4-ch REAR L-R) are also the REV audio channels in 2-ch. When entering REV Play, the 4-ch REAR channels must replace the 4-ch FRONT channels. The REVERSE relay mentioned above does this. There is only one control output from the Control Board that controls this relay. If FWD 2-channel plays normally in both channels, but only one plays in REV, the problem is probably with the audio switching....check the relay.