Speed issue with Dragon

[nakfreak]

Hi to all and Happy New Year! I have been lurking here for a while and it seems I have a problem. After my Dragon has fully warmed up and I record i find the music it records speeds up and slows down on playback. I am recording from a turntable and the source is not at fault since my other decks are free from this problem when put through similar tests. It has happened on playback before but I thought this was due to minimal usage however since it happened again I know there is a problem.

Any ideas. By the way I was using a XL11 for tape. I reside in Ontario, Canada and I am not technical inclined so I wont be repairing this. Everything else seems to work fine but a tune up is likely soon. The tape path, heads, etc are all cleaned.

Is there a qualified and experienced tech that can resolve this on this side of the border? If not where?

Thanks

[perry]

Sounds like a/few components on the motor control board. If you are not tech inclined, and are going to take it to be repaired, then it may be as simple as the electrolytic caps (especially the 470uF on the +12V rail), or the power transistors, which can fail due to heat over time. It also could be something as simple as lube that gets sticky when warm, but I doubt it, it is usually the other way around. Simple problem, not simple to lube, but if you can HEAR it speed up and slow down, then it is less likely to be lube. A tech could look at the test points on the motor control board with a scope and see how the difference signal looks, If it is all over the place, then at least you know where to start. If the signal looks good, then it may be the idler tire is shot, so the tension on the take up reels is not constant. Does it do it with all tapes? Less on a 60 min, worse on a 120 min? Does it do it in both directions? Is it worse in one? More details can help. The closest, reasonable time and price expert in the US, on Dragons is Nakdoc (Nashville Tenn, IIRC )..go to the main page and look under the DIY or Qualified techs section. Braxus may know a closer Canadian tech.

[Scorpion8]

Nakdoc is a member here and highly recommended. ESL is another Nak service station in US (New England) that many members use. http://www.eslabs.com/

[jazzgene]

Hi to all and Happy New Year! I have been lurking here for a while and it seems I have a problem. After my Dragon has fully warmed up and I record i find the music it records speeds up and slows down on playback. I am recording from a turntable and the source is not at fault since my other decks are free from this problem when put through similar tests. It has happened on playback before but I thought this was due to minimal usage however since it happened again I know there is a problem.

Any ideas. By the way I was using a XL11 for tape. I reside in Ontario, Canada and I am not technical inclined so I wont be repairing this. Everything else seems to work fine but a tune up is likely soon. The tape path, heads, etc are all cleaned.

Is there a qualified and experienced tech that can resolve this on this side of the border? If not where?

Thanks

Dragon is crystal referenced and is dead on. So there is something amiss. I have a Dragon and the speed is exact cold or warm. A 3khz tape recorded immediately after I received it back from ESL still plays exactly at 3khz. None of my other Nak decks can do this. Surprisingly, my Sony WM-D6C is almost as good as a Dragon speed stability wise. These units are crystal referenced as well.

I don't know any techs in Canada but I can recommend ESL.

[speakerman1]

Ther is a tech in Canada that is a member here. I have his info. I will PM it to you.
Larry

[Nakdoc]

Your Canadian tech should be able to repair your problem. If you remove the top cover, look at the circuit board mounted behind the mechanism. You will see 4 pairs of transistors side by side. One pair will be discolored. Replace this pair. 2SD882/2SB772. No adjustments will be necessary.

[perry]

Yeah, that was my guess as well..I had similar answer from some Naktalk members about those transistors. Easy enough to fix. I'd do both pairs, if I was was going to changing one.

[Nakdoc]

Nakfreak,
The motor drive board is easily removed. 5 connectors (the 2 pins are color coded) and one screw. You may send the board here. Wrap the board in aluminum foil to prevent static damage to the CMOS ics.

[perry]

Ever get it fixed? On Dragon number 3 I found a similar measurable W&F issue, though not audible. The motor control transistors wer definitely hotter than the other 2 Dragons. S0 I did a partial dis-assembly and slid out the capstans & cleaned and lubed the capstan shaft & bearings with some new sewing machine oil. Amazing difference. Dropped all the values to new lows for any of my decks, and the temperature drop was significant as well.