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Guest Simonon

Akai GX630db intermittent sound issues

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Guest Simonon

Here is a picture of my recently acquired Akai GX630db which appeared in perfect condition with no discernible tapepath wear. It however has not escaped the dreaded Hitachi 2SC458 intermittent transistor issue which happens to all of this series of deck. Basically you will notice the legs of these transistors have turned black with corrosion. This corrosion eventually migrates into the silicon transistor junction causing all manner of issues. Mine drops a channel intermittently and has wierd background noise on the other channel like a radio hetrodyning. All 30 or so of these transistors on the rec/ playback and dolby boards will need replacing with 2SC2240 types. Luckily I can do this myself plus a recap but if you had to pay a tech to do this it should be factored into your purchase if it has not been done. There is much on the internet about this issue. Worth the effort though as these are beautiful machines. The joys of maintaining old reel to reels.d8576dd7aac6173e0ac1e087dd319daa.jpg

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Lovely machine. Bigger better version of my 620 which sadly hardly ever gets any use these days.  Actually thinking of selling it, but with all it's faults, I'll probably get more for all the tapes. 

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Guest Simonon

Here is a quick follow up to my Akai GX630db. I pulled out the audio board and replaced all of the troublesome Hitachi 2sc458 transistors ( note these outhouse shaped ones are highly problematic) with Toshiba 2SC2240 types and recapped with Nichinon gold electrolytics. I do not like recapping vintage hifi for the sake of it but I found a number which were leaking having the tell tale brown spot on the pcb when removed so it was worth the effort.
The intermittent channel and hetrodyning background noise has gone with the unit sounding fantastic.
I did not have to touch any trimpots as it was in spec. All up much easier than expected but I would recommend a decent desoldering machine as it made life easy. I intend to tackle the power supply next and replace the dolby lamp which failed due to moving the unit around during repairs. Hope this info is helpful.5ceb7f808331333f6ffff19b27207112.jpgdec1fced84d920cc0273b9bb52e08455.jpgde263a15674276f87103e2f7a1b33be8.jpg64b03c1681eeba455b1336d6f0173c0a.jpgc8f639d681cd357dce884c9399ba9897.jpg116457561510d21db809c16d0bb2ceae.jpg

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Yes, good work mate.

It's amazing how many exhibitors are demoing at shows OS with R2R's. 

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Guest Simonon
Yes, good work mate.
It's amazing how many exhibitors are demoing at shows OS with R2R's. 
Yes it is interesting how they are back in vogue. I can see the prices of sought after units rapidly increasing on the second hand market. NOS parts are getting very scarce and pricey. I am also finding NOS genuine through hole components hard to source with potential counterfeit transistors problematic. Much of these through hole components are now 40 years old with stock hard to get. My Sudgen amp just failed catastrophically due to a counterfeit transistor from Ebay.
I still cant get over the price of the new Ballfinger decks €28k for the top of the line unit with the base model €12k.
Reel to reel is an expensive and challenging hobby to keep these old units going.666fade7df1d357235c1e44ed6a8608d.jpg

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