AKAI AA-5210 #2: Restoration
I have already restored it's sibling which means that I already have the restoration plan in my mind. Everything should be straightforward.
I am not going to repeat myself regarding part numbers and replacement component markings. In short I have used the exact same parts as for the first AKAI AA-5210 that I have been working on.
General Considerations
I should begin by saying that working on this amplifier presents a very big health hazard. There are lethal voltages inside. Not knowing what you are doing might result in severe accidents and possibly death by electrocution. I am very skilled in electronics repair and I have been doing such repairs for almost 20 years. This qualifies me to work in this field. But if you do not have experience, please take this information just as a knowledge base. Do not attempt to repair something that you cannot handle as there is a big probability to severe it further while also suffering accidents.
Good working condition tools are also necessary for this restoration. I am using a quality temperature regulated soldering station with multiple tips for every situation that I could possibly encounter. Also I am using a good solder pump and quality desoldering wick in two sizes. Isopropyl alcohol is handy to decontaminate boards of old flux and other residues. I also use eutectic formulation quality solder. Every replacement part is brand new, from a reputable manufacturer, ordered from U.S.A., Japan, or Germany. Also I only use parts that are suitable as replacements in various sections of the amplifier, after inspecting and comprehending the original schematic. Last but not least I have the years of experience backing up every action that I take while working on this unit.
I have found out that working with a temperature of exactly 300 degrees Celsius is sane for these vintage printed circuit boards. I have never lifted a pad with this temperature. But it is also true that I never wait more than three seconds with the soldering tip on a pad. While working on the chassis, I am pumping up between 360 and 440 degrees Celsius in the soldering iron.
Flux fumes are extremely toxic and should be avoided at all costs. Especially toxic are the fumes released while working on these old Japanese electronic boards.
Here are some before and after pictures of this unit.
96-5008 Power Amplifier Board Restoration
Here is the board before the job.
And here it is after servicing.
A5-5029 Tone Control Board Restoration
This is the board before the service operation.
And here it is after servicing.
A5-5028 Equalizer Board Restoration
Here is the board before the job.
And here is the board after working on it. Note the transistors mounted in reverse. This is due to the modern parts having mirrored terminal disposition.
A5-5026 Power Supply Board Restoration
Here is the board prior to restoration.
And after the job.
This concludes the restoration of this unit.
♫
|