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Akai aa5810 refurbishment / recap / modifications akai aa5810akai aa5810

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This page is written using English language only.

This Akai AA-5810 was refurbished during May, 2022.

Its power section was seriously burnt, and a blackened spot was in the power supply section too, I decided just go ahead and refurb without paying attention to the reason of defects.

All electrolytic capacitors and resistors were replaced throughout the amplifier, several film capacitors and most transistors also, a VBE multiplier modification was done in the main amplifier.

Enjoy the picture showcase.

The pre-amplifier part of the amplifier

The pre-amplifier consists of an equalizer/switch board, a volume/mike mixer board, and a tone controls board.

As the pictures show, taking this all apart, it is a real mess of wiring.

No big deal, just remember where every wire goes, replace some parts, and do some wirewrapping.

akai aa5810 inside akai aa-5810 preamp

The following pictures are about the equalizer/switch board getting new components.

Old situation on the left, new situation on the right.

akai aa5810 switches akai aa5810 equalizer

The following pictures are about the volume/mike mix board getting new components.

Old situation on the left, new situation on the right.

akai aa5810 mike mixer akai aa5810 volume

The already refurbished tone control board:

akai aa5810 tone control akai aa5810 toonregeling

The power supply, and the protection card.

The power supply is rather blackened, it needed some cleaning up.

The power output transistor measured still good, however, it was replaced and now it has a heatsink to get rid of the undoubtly present amount of heat dissipated.

On the pictures one can easily see the trouble area.

akai aa5810 power supply akai aa5810 bottom view

akai aa5810 voeding akai aa5810 voedingsprint

The renewed power supply mounted, new 10000 microfarad capacitors. To the right of the power supply board is the refurbished protection board.

akai aa5810 power and protection

akai aa5810 power and protection

The power amplifier

The main power amplifier looked like a warzone, both channels did have burn marks and bad components, as the pictures show.....

akai aa5810 heatsink koelplaat met transistoren

akai aa5810 main amp card akai aa5810 versterkerprint

The old power transistors were all different from each other.

akai aa5810 heatsink koelplaat met transistoren

The main power amplifier empty card. All transistors were replaced, TO-5 type of transistors were used instead of the Motorola-type and the TO-220 ones.

The transistor mounting holes location in the card suggests it was designed to accomodate TO-5/TO39 transistors already, but the orientation is the wrong way around.

Therefore, the transistors I wanted to use did get their base legs moved to the other side below the plastic standoffs before mounting.

Additionally, I did get rid of the diode/NTC type of temperature sensing, I did mount a BD329 transistor as sensing element/VBE multiplier circuit.

akai aa5810 main amp card akai aa-5810 TO-5 TO-39 transistor akai aa5810 BD329

The circuit card was rebuilt, using the TO-5 / TO39 transistors probably makes it look more nice compared to when it was new.

akai aa5810 amplifier pcb

The wiring is a little bit tidier and the BD139 heat sensing transitors are mounted using a ceramic heat conducting pad, intended for TO220 devices.

akai aa5810 main amp card akai aa5810 versterkerprint

The new power transistors, and in the background the remounted other circuit cards.

akai aa5810 heatsink koelplaat met transistoren

akai aa5810 front

akai aa5810 top voorkant

The special loudspeaker connectors were replaced using banana sockets.

akai aa5810 achterkant back

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