Akai X-355 Amp problems  

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Auskelpie
(@auskelpie)
Active Member
Joined: 10 months ago
Posts: 6
29/05/2018 1:37 am  

I have just purchased an Akai X-355 unit off eBay! Was told that the unit was in working condition and all it needed was a good clean and service? Well after doing that I found out that there was no response from the left amp on playback in any of the modes IE 4 track mono or in full stereo in both directions of tape transport. All of the mechanical’s are working fine and the heads are in excellent condition for their age. So can anyone help me by pointing me in the right direction to obtain a complete service manual! I have looked in the usual spots on the web but what is available are incomplete. Kind regards, Malcolm. 


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Admin
(@admin)
Member Admin
Joined: 2 years ago
Posts: 15
31/05/2018 8:18 pm  

Hi Malcolm

Welcome back and hope you are well? 

The schematics and service manual can be obtained at  https://www.hifiengine.com/manual_library/akai/x-355.shtml

I can download the schematic but not the service manual, showing an error that my IP address has changed.  Wow! In any event if you need the schematic let me know. I think that’s all you will need.

The preamplifiers follow a pretty much straightforward design but the relay switching seems to be quite complex.  If the VU meters aren’t registering any signal I’d drive it from the line or mic in first.  If the VU meters are registering a signal the power amplifiers are simple class AB driver transformer coupled devices and I’d touch the inputs with a finger or listen for hiss. (volume control wiper, no attenuation). Nothing like a buzz to get the creative juices flowing.

If the seller says it was working and needs a clean I’d look at the relay block.

Let me know if you get stuck and we’ll do a point to point check together.

Cheers

Ian


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Auskelpie
(@auskelpie)
Active Member
Joined: 10 months ago
Posts: 6
02/06/2018 8:19 am  

Hi Ian

Thank you for the reply, For your info I did download the service manual for the suggest site (i head there every time!) but that manual is missing a number of pages? and it is also not the best of scanning also it is all over the place. But I shall take your advice and try and use your methods and see how I go.

On a side issue since we last spoke my red & Tan Kelpie Jett crossed over the rainbow bridge three months short of his fourteenth birthday a very sad time as he was my constant companion. If I knew how to upload photos I could send your some photos of my previous Kelpie Tess who did what your dad’s Kelpie did, that is ride around with him on his motor bike! Tess did it also she  just loved it. 

Kind regards from Down_Under

Malcolm.

PS.. Turned 81 of the 31st. cannot believe I have lasted this long!!!??? 


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Admin
(@admin)
Member Admin
Joined: 2 years ago
Posts: 15
03/06/2018 6:20 am  

Hi Malcolm

I am very sad to hear this, Kelpie’s make such good friends that this must have been heart rendering for you. Also I must commend you for keeping up this hobby at 81, that’s what keeps you no doubt young and strong.

With regards to the Akai, I only downloaded the schematic and the electronics use Ge transistors, the configuration such that it shouldn’t be that difficult to fault-find.  The switching though, that’s another story altogether.  😯 

I doubt a cap would cause total failure like you have unless one of the component legs has corroded off. (I have had that before though). 

Best of luck and keep well!

Cheers

Ian


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Auskelpie
(@auskelpie)
Active Member
Joined: 10 months ago
Posts: 6
04/06/2018 1:14 am  

Hi Ian 

Thank you for your thoughts re Jett it has been very hard without him but I shall press on!!. With regards to the Akai I will follow your advice and see what happens. But where did you get a full schematic of the unit? What I found on that site and many others that have the same scan, to me the schematic is in complete! One of the worst downloads I have ever had for that site. Or am I just a bit grumpy. 

Kind regards

Malcolm.


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