Akai GX-625 Reel to Reel Transistor & Capacitor replacement 

Hello, Darren. It's really nice to see young people rolling their sleeves up (not literally in your case) and replacing components in printed circuit boards, so well done! I have a gx365 that I have to admit I haven't used in decades but I really should roll my sleeves up and replace the electrolytics and maybe some of the transistors as well.

Recapping it is one of the most important thing to do. Good job.

I'm going to buy one in two days, it's refreshing to see that it's not that impossible to service it. I'm quite familiar with electronics but I was scared as hell to open up something like this. Cheers for the video

Good evening, I bought the Akai gx 625 used and I was aware that it would need a total overhaul. All this happened with the replacement of all the transistors of the preamp section and with the replacement of some electrolyte capacitor. The machine has been cleaned lubricated and calibrated. It works great and is perfect aesthetically. The technician to whom I brought it could not solve a big problem. The recorder has a great background noise that feels very pronounced when the music is stopped and the tape is flowing. I tried to record a piece of tape with volume at zero. When i listen to it again with the volume of the recorder on the second line it starts to be audible. This problem makes me listen to the recorder with the amplifier volume at 80% of its power and with the output volume of the recorder on the first line. The noise is not in the tape because in another recorder it sounds perfectly. Thanks for your help.

Special Thanks. My first Machine. The next to repair. ;-) Nice Video.

Looking forward to the calibration vid. I'll be there soon in my Akai 4000ds revival project. Never done that before.

Beautiful deck. Thanks for the video, looking forward to the next one :)

akai's try a teac A3340 changing the lamps under front panel it's a lot harder i had to do it great to see young man getting into fixing them i gone over to 1/2 tapes because 1/4 inch price'sare crazy high i use 7 1/2 on a tascam 38 new eq settings saved money in the long run

Have a GX-635D which will need this as well. Theres 16 2SC458's in it. A bit scary as I've never monkeyed with electronics before but it does seem straightforward.

Thank you 🙏

Thanks for the informative video. Did you have to use special audio caps or normal electrolytics?

Any chance of the calibration video you mentioned? In what way is the sound better when the transistor and capacitor mods are done? Thanks !

Exceptional

Saludos!

hi have worked on alot of tascam 34-38 they can be a right pain to fix best to leave the audio boards don't need re cap the logic board is the pain there's a 2 watt 1.5k res i have had bad time with and the 24v line on the logic pcb like you best to keep to the home decks they don't play up like the pro decks

Hi Darren I was wondering if the 2sc1845 transistor was the same polarity ? I’ve heard it was inverse compare to the original? I’m repairing a 4000ds mkii

I didn't realize that a transistor can go bad. I thought they either worked or they just did the "fastest fuse" thing. Do they lose linearity or something? Also, what brand of cap do you use? I tend to go for nichicon, or rubycon, or nippon chemi-con.

Hello. I enjoyed your video on servicing. I am glad that you mentioned that some transistors pin outs are different. Also what brand is your solder sucker?

Mui lindo aparato

Muy buen trabajo

I have a 1960s ultra (FERGUSON) UNIT.New belts coming but..is it worth replacing any caps or just leave it? Does gave HT line as there is a valve Cheers

So if I replace some 2SC458 to BC549 I have to switch because the pinout is the other way around..I'm just asking for confirmation thank you

Would like to know what is your desoldering tool make and model. Have not seen one like that before.

When using a vacuum cleaner be very careful not to cause any static discharge or arcs.

Congratulations sir..! I have a GX 266 II and I've just finished replacing all the electrolytic capacitors with NICHICON caps of which I've specially ordered abroad..What about tantal caps..? The recording is not that good for me..%80 of the transistors are renewed..Should I go further..? Thank you very much..!

Great work. I also have an Akai GX-625. If I may ask, When I put in reels, supply and take up, the function buttons do not work. Could this be a blown fuse? Thanks in advance.

Thanks for the video, do you think only the transistor change would do the trick to reestablish the sound or capacitors change are also vital in this case?

Hello, and how long did it take to do that job?

Hi, you change 458 & 945 transistors or only 458?

Hi Darren, great video, thank you. I have the task of getting both a GX-4000D and a GX-630 in working order. I will replace the 2SC458s for sure, but I'm on the fence about the electrolytic caps - trying to decide how much time I have to put in on these machines. When you replaced the caps on your deck, did you happen to test any of the old ones once you desoldered them, and if so, how far out of spec had they drifted, generally? Hats off to you for replacing them all, perhaps I will, but it would take me longer than one night I suspect : /

Hello, very nice video... I bought a 625 last year, and, because i have also a GX 215D, i knew the issue with 2SC458.(replaced with low noise BC549 if i can remenber well--) I immediatly changed the transistors and all went fine. But not the capacitors.. I will do that, it is a good idea. Did you use good quality caps?

Hi Darren Why did you not used the 2sc458 and 2sc945 transistors?

Hi Darren! I was wondering if you might be inclined at all to do a vid on calibration? Many thanks!

My Akai GX-4000D r2r right channel (from the RCA output jacks in the back) does not work. Everything else, including the front headphone jack, is fine. That is, sounds from both channels (L and R) are sent to the headphones but the R channel is NOT output via the back RCA R channel output. Do you what went wrong?

Hi Darren, nice video, how did you calibrate the deck afterwards??

I am about to do the same to a GX210D.. Lost one input suddenly. The same shit transistors in it.

I have an Akai GX255 and the transistors (2SC458LG's) and others have been replaced. The deck sounds amazing except there is ridiculous hiss coming out of the output stage without tape playing. I suspect this to be the transistors?. Have you seen this before and can you suggest replacements?. Thanks for any help Cheers Julian

Hello, I have a GX-625 that is in very nice condition as well. I am having an issue with the digital timer though. when it starts out, it counts up fine until it gets to about 500 feet, then the digital display goes haywire. or if you reverse the tape and it goes to 9999 it will do it almost immediately . I have had it to a repairman and he couldn't figure it out, also another one told me not to bring it to him. any ideas of what the cause could be? ps: it worked fine when i got it, then just started doing this. also it blows an 800ma fuse and the screen goes out. thank you for any help

Thank god newer Maxell tapes don't have the tape hole in the reel. Dont use it period

Why change working transistors? Either they work or not, its not like caps.

Не знаю как в этом магнитофоне, но в Акае 635 ни один конденсатор не полетел, а вот транзистор шумел и то один всего.

what is a good place to get old transistors like 2SC458LG

now...next job is repair MINE AKAI GX-625 please 👍

why didn't you rebuild the power board? mine drifted and smoke the logic circuit.

what transistors you replace the old ones with?

hi re cap on this is easy re cap a teac 3340 the first quad they did is hell lot harder AKAI GX77 with bad capstan the audio board come out the same way asm your and the rs 1700 1500 is easy to get at tascam 32 to 38 is easy to do as well

Thank you darren for this video...I have a GX635D, that will also need doing...:-) Also i have a problem with green led that does not light up ,It powers up but it is not working...Any adeas? Thank you...:-)

Do you remember what capacitor values you needed? Sure be nice if someone would just put a kit together :)

My GX 620 work perfect for 45. Dont need TLC. All new transistors are low power then original transistors 2SC945 . Amplification factor for new transistors is weak! If the transistors and .capaccitors are made in china you pull out JAPANESE accuracy. Like Sanyong SUV clone of Mercedes ML.

Hi I have a GX4000D that needs some work if your interested?

blowing out dust is no added value, nor is it a revision

Darren, I'm looking at purchasing one of these 625s without a mains lead. It seems to be a two-pin input - do you know if replacements are readily available?