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There are currently no product reviews.
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Excellent just what I needed to replace the electrolytic caps and make this old gem a beauty again. Was as scan of the original photocopied service manual.
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It was helpful to get schematic with waveforms in important points and lot of service information. Manual is good quality, fast delivered. Of course it is hardcopy of paper one with all its disadvantages.
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I want to give you a real heads-up for your desire to enable such people as I to acquire the information I need to maintain the older types of equipment such as this Akai HXA351W. You do a swell job with all the processes you have to perform so I can have a legible, thus usable
document which does not send me crazy trying to figure out the blurry text of a bad copy.
Very well done, Thomas.
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This manual is very well presented and after printing out looks about as close to an original as I think you can get. The quality is second to none.
The content of the manual is comprehensive and I think it would be well suited to an audio repair professional which I'm not but I did find it very informative and helpful.
The cost of the manual is more than covered by the money I'll save when I change the keep memory battery now I have the relavant info.
Very pleased with my purchase and can recommend it wholeheartedly as I can other manuals I've downloaded from this site.
Regards
Limey Alex
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Complete manual including mechanical part in good pdf quality. Shaded greys of the pcb due to pdf not perfect but usable.
The basic voltage range of the servo systems i s 0 to 5 millivolts for the Y axis and 0 to 7. 5 millivolts f o r the X axis for full scale travel. Operation with g r e a t e r voltages is obtained by means of a step attenuator inserted between the input terminals and the balance circuit. Each range step may be made continuously variable by operation of a transfer switch which i n s e r t s a variable potentiometer and extends that range to about five times i t s fixed value. The range position i s selected so that the amplitude of the input data will be within the travel limits of the instrument. Included in the input c i r cuit is a variable filter which minimizes undesirable noise and ripple disturbances in the input signals. After passing through the input filter and attenuator, the input signal is applied to the balance circuit, where it i s cancelled by a n internally supplied opposing voltage derived f r o m a reference cell and potentiometer. Under these conditions there i s no signal output f r o m the balance circuit and the servo system is a t rest. When the input signal changes to a new value it is no longer canceled in the balance circuit and the unbalance voltage, o r e r r o r signal, is applied to the chopper where it is converted to a 60-cycle form. The A C output of the chopper is amplified and applied to the control winding of a two-phase servo motor. The motor is mechanically coupled to the balance circuit potentiometer and thus changes the balance voltage until it again cancels the new value of input signal. If the input data is constantly changing at r a t e s within the capabilities of the instrument, this rebalancing action is continuous. Thus the positions of the balance circuit potentiometers and of the pen and c a r r i a g e , to which they a r e coupled, a r e always directly proportional to the amplitudes of the signals a t the respective input terminals. The use of the X-axis with a variable input voltage o r as a sweep circuit is selectable by a function switch on the r e a r panel. Operation of the time base i s dependent on the f a c t that the charging current taken by a condenser will a s s u m e a constant value when the charging voltage i s controlled so a s to inc r e a s e at a uniform rate. Existing facilities of the r e c o r d e r a r e utilized to apply a linearly increasing voltage to the X-axis servo amplifier causing the pen to advance at a uniform r a t e in total sweeps dependent on the constants switched into the circuit. These constants a r e so selected during manufact u r e that the time required for full scale pen t r a v e l equal, in seconds, the numerical values of the millivolt steps of the X-axis range selector. The Model 2s Autograf consists of t h r e e major assemblies: novable aluminum case. >ase plate assembly, mounting the amplifier chassis (which contains m e chopper, two high gain amplifier channels and a power supply for the amplifier), the various input plugs (mounted on a side panel), the r e f e r ence cells, the p r i m a r y power control panel, and the vacuum pump.
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