I got Nakamichi Dragon for full service. Visually it was in very good shape but owner complains that deck not sounds as it should. It was purchased from web and no records about deck's state.
As deck's mechanism was »dead« i need to rebuild it before anything else.
After inspection real state shows:
Mechanism was rebuild and as was out of deck i also replaced all electrolyte capacitors in power supply…more space to do, if mechanism is out.
I put mechanism back and 1st measurements started.
Playback frequency response isd horrible…it starts to rolloff already at 4kHz …in both directions…on both channels. Never seen this before…wow. If i was not at mechanism rebuild aligned heads, will said thst someone messed with heads. Still i checked again if maybe i made some mistakes but no…all heads are perfectly aligned so this can't be a problem.I found that also some capacitors are replaced on playback amp and also on recording section. More solderings…replaced caps with original ones…but still no better results. Then i started to suspect playback head. I removed head, inspected under microscope and there was some wear on but i saw heads in worse shape and they worked normally. So what to do…to get another Dragon head…even used one is mission impossible. Hmm…
Then i remeber that Nakamichi TD-1200…car cassette player have »same« head. Actually it is not the same…it have different shape. On the net…specially on TapeHeads forum was lots of discussions about this, but all said it is not possible to replace as simply will not fits.
I have TD-1200…so lets take head out and see what can be done.
Yes…head is bigger then original Dragon head BUT…with some modifications can be attached to original holder. Also electrically they are the same…coils have same values as Dragon's head so no further modifications on playback amp. I will not go in details but after some quite time i sucessfully installed head…on right position and right height. As i didn't wanted to remove cables from original head i add new ones.
Now as head is installed correctly to head holder and put on headblock another problem shows. Padlifter. As head is bigger…padlifter not fits. Another modification follows and padlifter fits.
Now ther most exiteing part…measurements…damn…i hope i did someting
I inserted level tape…matched…same as before…good. Track alignment tape…set. Azimuth tape…set…repeat this 3 times…done. Now reality…frequency sweep 20Hz to 20kHz…
…And rest is history…deck goes over 20kHz like a charm compared to 400Hz.
Now need to adjust to be flat in range in +/-1dB, but this now will be simple task.
As you see, there is solution for dead Dragon playback heads, just need to show interest and take time.
https://www.cassettedeck-service.com
As deck's mechanism was »dead« i need to rebuild it before anything else.
After inspection real state shows:
- Doors can't be opened
- Bottom left holder for mechanism is broken
- All 4 screws which holds mechanism to decks frame were untighten
- Headblock movement is laggy
- NAAC motor housng is screwed with 3 screws. 1 screw missing. Also those 2 screws were not tighten
- NAAC motor screwed with 2 screws. 1 screw is missing
- Backplate with thrust bearings were not tighten
- Intermediate mechanism plate were not tighten
- NAAC can't worked as pin from cable was out of pin holder
- NAAC motor cable is cut and soldered back. (someone was lazy to remove connector)
- Erase head cable is cut and soldered back. (someone was lazy to remove connector)
- Missing C-clip on roller inside of CAM gear
- Take-up reel table surface is sanded
- Pinchrollers are not original, but from Blackreel
- Supply tape guide was 0,7mm out of alignment
Mechanism was rebuild and as was out of deck i also replaced all electrolyte capacitors in power supply…more space to do, if mechanism is out.
I put mechanism back and 1st measurements started.
Playback frequency response isd horrible…it starts to rolloff already at 4kHz …in both directions…on both channels. Never seen this before…wow. If i was not at mechanism rebuild aligned heads, will said thst someone messed with heads. Still i checked again if maybe i made some mistakes but no…all heads are perfectly aligned so this can't be a problem.I found that also some capacitors are replaced on playback amp and also on recording section. More solderings…replaced caps with original ones…but still no better results. Then i started to suspect playback head. I removed head, inspected under microscope and there was some wear on but i saw heads in worse shape and they worked normally. So what to do…to get another Dragon head…even used one is mission impossible. Hmm…
Then i remeber that Nakamichi TD-1200…car cassette player have »same« head. Actually it is not the same…it have different shape. On the net…specially on TapeHeads forum was lots of discussions about this, but all said it is not possible to replace as simply will not fits.
I have TD-1200…so lets take head out and see what can be done.
Yes…head is bigger then original Dragon head BUT…with some modifications can be attached to original holder. Also electrically they are the same…coils have same values as Dragon's head so no further modifications on playback amp. I will not go in details but after some quite time i sucessfully installed head…on right position and right height. As i didn't wanted to remove cables from original head i add new ones.
Now as head is installed correctly to head holder and put on headblock another problem shows. Padlifter. As head is bigger…padlifter not fits. Another modification follows and padlifter fits.
Now ther most exiteing part…measurements…damn…i hope i did someting
I inserted level tape…matched…same as before…good. Track alignment tape…set. Azimuth tape…set…repeat this 3 times…done. Now reality…frequency sweep 20Hz to 20kHz…
…And rest is history…deck goes over 20kHz like a charm compared to 400Hz.
Now need to adjust to be flat in range in +/-1dB, but this now will be simple task.
As you see, there is solution for dead Dragon playback heads, just need to show interest and take time.
