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Old 29th Apr 2019, 10:15 pm   #10
REDGUUZ
Triode
 
Join Date: May 2017
Location: Assen, Netherlands.
Posts: 13
Default Re: Akai GX-270D No FFW / RW

Sorry Moderator, to disagree.

You assume that only electorlytic capacitors have been replaced on the Power supply board but it is not at all a confirmed fact that other cpacitors (MP: C5 and C6 (0.47uF /250V) and spark quenchers: CR2 and CR3 (each : 0.1 uF +120 Ohm) have not been replaced, as well.

Also, it is, in my opinion, quite relevant to continue this thread as member MS660 was so kind to unravel the schematic, see preceding posts.

Member MS660 showed that spark quenchers CR 2 and CR3 and the MP capacitors C5 and C6 (0.47 uF , 250 V (NB these are not the regular motorcapacitors) have a profound influence on the reeling operation.

The Hitachi metal tubular MP capacitors (e.g. C5 and C6, 0.47uF, 250V ) have generally a poor track record in AKAI equipment (electric leakage, even emitting their waxy content);
The black spark quenchers (Brand Okaya) used in AKAI's and TEAC's are on the other hand, normally very reliable.
(Note that the European RIFA Miniprint spark quenchers (also used in some AKAI equipemnt for the CEE/UK market) on the contrary have a failure rate of 100 %, not only in AKAI equipment, but also REVOX and many household items (washing machines, hoovers etc.).

However in this deck, AKAI elected to use another (unknown) brand of Spark Quenchers (Blue type), of which the reliability is unknown.

Note: The Electrolytic capacitors on the Power supply board are governing the 24 Power supply and totally not related to the reel motor problem; hence irrelevant.

This triggered my question, whether indeed the MP capacitors C5 and C6 and/or the spark quenchers CR2 and CR3 had been replaced by Dave, because he claimed that the sluggish reeling was cured.

Maybe MS660 (or another member) could comment whether a failed CR2 or CR3, and/or a partially failing C5 or C6 could result in a poor FF reeling problem, whilst FR reeling is OK, as well as Forward and Reverse Play.

Any comment on the above is highly appreciated!

I will perform a full recap of the power supply board, in any case (not only the electrolytic capacitors, but also the MP's (C5 and C6) and the spark quenchers).
Time will tell whether this is the solution!

Kind Regards, Martin
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