The Aiwa HV-FX1500

The Aiwa HV-FX1500 was a popular NICAM video from the 90s. A fairly simple construction with mainboard & tuner & seperate upright nicam panel, The deck plugs into the mainboard as a complete unit which is great for deck servicing, If the deck is to be tested outside of the main unit a set of extension leads are available.

The 10v regulator IC503 (TA7810S) which uses the deck itself as a heatsink can sometimes get quite hot & can cause the deck assembly itself to get fairly warm (this has sometimes caused us trouble with sound warble or mistracking) Unfortunately there is no easy way to cure this, the reason being is the regulator has to drop too much voltage, The voltage from the transformer can be quite a bit higher than the 16.5 volts quoted on the circuit diagram, We have found cases were 10-15 watts of heat is being pumped into the deck.

Apart from the above problem the unit has proved fairly reliable, below are some of our recent fault experiences.

Dead, no display, fuse F502 [2AT] blown.
Check power supply diodes D501, D502, D503 & D504 (All DSA12TB)

Dead, no display, fuse F503 [3.15AT] blown.
Check power supply diodes D505, D506, D507 & D508 (All DSA26C)

No fluorescent display.
Check circuit protector ICP501 (0.315A) in the p.s.u 30v circuit for o/c

Will not accept cassette, Loading motor does not operate.
If 12v is present across pins of connector CX5002 when attempting to load a cassette suspect failure of the loading motor, if voltage low/missing check for 0.8v at the collectors of Q1015 & Q1016, if 0.8v is missing suspect the cassete l.e.d or the end sensors, If 0.8v present check resistors R1092 & R1094 then check for 6v at pin 14 of CX1011 before suspecting IC1001 itself.

Powers off after 3 seconds.
Check the loading belt, Then for capstan & drum rotation

No power on, Display ok
if the power "on" switching at pin 2 of power supply connector CY1011 is not present check transistor Q1014 then trace back to pin 36 of IC1001 If power "on" switching at pin 2 is ok check resistors R508 & R509 & Diode D514 Before suspecting 14v regulator IC501

Powers off after 6 seconds.
Check the reel belt, if ok check the reel sensors

No drum rotation.
Check for 12v d.c at pin 18 of connector CX4004, If missing trace back to p.s.u if all ok check for 2.4v at pin 16 of IC1002 if present check resistors R1015, R1016 & R1123

No drum rotation, power to drum ok.
Check for failure of the stator motor M2003 [PART No.S5895110070]

Stops after few seconds in rew/ff/play/record, capstan motor turning.
Check for reel sensor pulses at pin 62 of syscon chip IC1001 (OEC8057C) if missing check R1062 & R1033, if pulses present check back to pin 11 of connector CX1003 (Also check for 5v at pin 10 of this connector) if reel pulses are still missing suspect reel sensor assy itself.

No playback picture, E-E picture ok
check for fm waveform at pin 14 of IC4001 (LA7439) if missing check capacitor C4103

Int loss of picture in playback or E-E.
Check IC502 [PQ05RF21] for dry joints / intermittent failure

No E-E
Check for correct voltages at the tuner B+(5v), TU(30v), PB(5v), B+(9v) if incorrect trace back to p.s.u, If voltages ok check for video at emitter of Q6001 (From pin 18 of tuner) before suspecting the tuner unit itself.

Audio signal missing / incorrect, no audio bias
Check for 9.2v at collector of Q5001 if incorrect check transistor Q5003 & osc transformer T5001 for open or short circuit winding. Record / E-E switching of audio chip IC5001 (LA7286) is via pin 24 (5v in record mode)

Copyright © 2000 - 2003 - E.C.S (Technical Publishing)
Site Design & Layout © 2000
All Rights reserved

All Information is supplied as per our Site Terms.
Use of this site deems your acceptance of these terms.
Click links to view our Site Terms and Privacy Policy