Cam belt on Dragon??

[perry]

Anyone know if the cam belt on the Dragon is the same as the one on the RX-505? I've 2 505s and bought a few belts, soI have spares. The Dragon I just got has that classic "cam belt" screech whenever the tape stops or is reversed. I haven't opened it up yet to check. They are both from the same time period and both have the classic "silent mechanism", but I would think the actual cam functions would be different. I'll check Naktalk as well, but you know how long that takes.

[Nakdoc]

it's the same belt
Perry

[perry]

Thanks Nacdoc, you da man! Sort of academic now, as I opened her up last night to lube the cam shaft (which eliminated the screech, just like on the 505s) and all the belts are pretty floppy/loose, but work as required. The idler tyre has slight visible checking on it, as well, so I've ordered a rebelt kit. Plays beautifully tho, and the NAAC works perfectly. Very pleased for a bit over $400. Plus, a nice high serial number, 245XX, can't remember the last two digits. Spotless inside. Here are few shots of the business end of the belts and the heads. Pinches need a good cleaning, but rotate freely, as do the spring loaded tape guides. A very slight tick-tick in the supply reel side, (may be nothing, have to investigate, as it seemed to change depending on tape used), and curiously if you put your ear right up to the opened door, there is a definite audible motor hum, can't be heard 6 inches away though..normal?

[Nakdoc]

When I tested generic belts vs. genuine Nakamichi belts, I found the original stretched capstan belts performed better than all the generics!
Fred at Marrs took this info to heart and had the 8096D (aka Gold) belt made to the original specs, so nak lovers would not be stuck beltless in Seattle.

[perry]

Yes I orderd a few D3 belts from him for the 505s. Work great. These are obviously not as critical. I ordered and got the belts & idler from www.beltkits.com, where Joe has a limited selection of kits that he puts together with incredibly detailed instructions and tons of accurate color cad drawings, that seriously, took a ton of work to draw, comment, and number. For the Dragon, it literally is a 10 page, screw by screw, connector by connector, with full color detailed cad drawings (just like he describes), and where to be extra careful. Easily worth the extra cost over just belts for the DIYer that needs more than just an exploded parts drawing. Now I haven't actually followed it yet so I can't vouch for it's completeness, but I will, soon. It reads wonderfully.

[Dragonbreath]

Yes I orderd a few D3 belts from him for the 505s. Work great. These are obviously not as critical. I ordered and got the belts & idler from www.beltkits.com, where Joe has a limited selection of kits that he puts together with incredibly detailed instructions and tons of accurate color cad drawings, that seriously, took a ton of work to draw, comment, and number. For the Dragon, it literally is a 10 page, screw by screw, connector by connector, with full color detailed cad drawings (just like he describes), and where to be extra careful. Easily worth the extra cost over just belts for the DIYer that needs more than just an exploded parts drawing. Now I haven't actually followed it yet so I can't vouch for it's completeness, but I will, soon. It reads wonderfully.

Perry pls let me know how it went. I've read about there being a black idler and white idler on some Dragons and how some idler tires don't work well so I am severely interested in your work right now.

[gamve]

Yes I orderd a few D3 belts from him for the 505s. Work great. These are obviously not as critical. I ordered and got the belts & idler from www.beltkits.com, where Joe has a limited selection of kits that he puts together with incredibly detailed instructions and tons of accurate color cad drawings, that seriously, took a ton of work to draw, comment, and number. For the Dragon, it literally is a 10 page, screw by screw, connector by connector, with full color detailed cad drawings (just like he describes), and where to be extra careful. Easily worth the extra cost over just belts for the DIYer that needs more than just an exploded parts drawing. Now I haven't actually followed it yet so I can't vouch for it's completeness, but I will, soon. It reads wonderfully.

Hi Perry,
Any chance of some high quality scans or copies of the cad drawings for the instructions. They would be invaluable for the site as long as permission from the author is obtained.

[tcp100]

Hi Perry,
Any chance of some high quality scans or copies of the cad drawings for the instructions. They would be invaluable for the site as long as permission from the author is obtained.

Not to spoil the party, but I don't think Joe would be up for this.

I asked him for a copy last week, and he, within his full rights and absolutely correctly, said that these instructions were the lion's share of the work in his kits. They're really what separates him from the millions of e-bay sellers. (Not to detract from Fred at marrs - his belts are top quality; I got a set from him for my Sony.) Joe said he was hesitant to even sell the instructions alone worried they'd get out on the web or something. After seeing them, I can't say I blame him.

Joe has put a TON of work into these instructions - they are nothing short of amazing.

He definitely convinced me to shell out the nominal amount for his kit, and from what I see (again, haven't followed it yet) - it's worth it.

Joe's done this for dozens of decks, not just the Dragon - so I suggest anyone looking for help in these matters check out his site (www.beltkits.com).

[gamve]

Not to spoil the party, but I don't think Joe would be up for this.

I asked him for a copy last week, and he, within his full rights and absolutely correctly, said that these instructions were the lion's share of the work in his kits. They're really what separates him from the millions of e-bay sellers. (Not to detract from Fred at marrs - his belts are top quality; I got a set from him for my Sony.) Joe said he was hesitant to even sell the instructions alone worried they'd get out on the web or something. After seeing them, I can't say I blame him.

Joe has put a TON of work into these instructions - they are nothing short of amazing.

He definitely convinced me to shell out the nominal amount for his kit, and from what I see (again, haven't followed it yet) - it's worth it.

Joe's done this for dozens of decks, not just the Dragon - so I suggest anyone looking for help in these matters check out his site (www.beltkits.com).

Thats fair as far as I am concerned. I was trained as a design engineer and I know how much work goes into just a basic AutoCAD drawing. If Joe has done all this off his own bat he must have spent hundreds of hours drawing and editing.

The only way one should get these instructions is to buy the kit. This being the case we should have a section on the site to list contacts for these types of resources. I guess it could go under the machine brand in a section called contacts and resources?......Waada you recokn Scorp, Broons, Des?

[perry]

What is nice about these instructions, is that with a little common sense, they work for many of the classic mechanisim decks. Naturally, the electrical PCB connectors will be different for each one, but none are as crowded and cramped as the Dragon, so they would be only easier. I would seriously doubt that the author would allow a general posting of his intellectual property, as that IS his selling point. Real insructions, that took hours of time to layout and CAD. I had no problem paying him for them. The kit is often on ebay and goes for about $28..I didnt want to wait, so bought it direct for $30.

I completed the 4 belt changeout this past week, and everything works great. To be honest, his idler tire was the best fitting of the 3 different ones I bought. Correct OD, slighly smaller ID for a tight fit, but about 0.25mm thinner, for the white hub. It has worked perfectly so far. No wobble, noise, stutter, etc. The first one was defective, but he mailed me another one ASAP, which I used. According to Nakdoc, the ESL and Marrs ones, which are identical, work fine on the black hubbed classics, but I would NOT use them on the white hubs. I installed the Marrs one first and there was MAYBE 0.5mm of black rubber showing past the sides of the white hubs, vs the 1.5mm of the OE tire. In addition, the ID is significantly smaller..you have to REALLY stretch the tire over to fit it on. ESL will sell you an OE replacement tire for $120USD + S&H. Seriously. Nakdoc cuts down his own from IT-6 tires bought from Union Electronic Distributors to make them the right width (3mm).

The counter belt for the Dragon from Beltkits was perfect, the Marrs one a little thicker. I prefered the thinner one to provide more clearance by the spring and to provide less drag on the take up reel. The Marrs cam and azimuth belts were a better size and fit than the beltkit ones.

Now that said, his instructions were lacking in a few important areas. Some I'm sure because there are going to be variations depending on the age of the deck. Some, however, are just plain shortcomings. like remember to remove the cassette door cover first. Might not be obvious to everyone that it jsut snaps up and off. I have no problem pointing out issues I ran in to.

1. The wire colors and even connector colors that he references did not match on my deck. At all. Well, since most of the connectors are white, I guess they matched, and there is one black connector so it matched...but blue and red ones? NADA. Wire colors, or even design. Nope. Also, he states that "you can't get them mixed up"...again, not really. Of the nine connectors, there are something like 1- 6pin, 2- 5pin , 3- 4 pin. 2 -3 pin, and a 2pin. So the singles are easy to match, but almost any of the wrong same size ones can be swapped, so MARK EVERY connector as you remove it on both the PCB and the connector, except the one 2 pin. Also, he doesn't show routing. Take pics or sketch the routing for each connector. You will have to rotate that deck into every orientation and will lose what went where REAL fast.

2. He only provides 3 ty-raps. I cut out at least 10-12. Not an issue for me, I have hundreds of ty-raps, but it might be for Joe Average.

3. He instructs to remove circuit board #1 and 2, I think. They cannot be removed on my deck unless you de-solder some pretty hefty ground cables, which I was unwilling to do, so I had to work with the boards still wired up.

4. He doesn't tell you exactly HOW to remove the mechanism, just a general, "twist the cassette door to clear the frame". You need to remove the rod that connects the power switch to the front panel (it pops off), and you will be removing the mechanism through the top. Be VERY careful of the NAAC bowden cable (blue plastic sheathed strip). It might have been obvious to him, but the reason you disconnect all those 9 connectors is they are wired to the mechanism assembly, so you have to extract each connecotr and cable through Naks rat nest of wiring as you remove the mechanism, to prevent damage.

5. When you start to separate the capstan motor back plate from the mech, and separate the two mechanism halves, there are thin black washers on each of the nylon posts. He makes no mention of them and they tend to stick to the metal side, and then fall off. I lost 2, and had to fish two out from the nylon gear/cam areas. Had I not noticed them, they would have jammed it up for sure, not to mention I would not have put them back in place. Mark the screws and holes as you remove them. Many are different lenghts and diameters.

6. He tells you to just pull out the capstans, but makes no mention of the small nylon washers that protect the bearing face for the capstan, that are on the head side of the deck. They will fall off and get lost if you are not careful. (amended per Nacdocs advice):Pull them straight out, and all the way at once. Do not ever let them hand down. Handle them like they were gold. The shafts can bend easily, and if they do, even the slightest, you got yourself a couple hundred dollar paperweight.

7. To separate the two halves, you have to remove the friction pressure keepers that hold the capstan motor sensors in place. These are potted/glued down, to prevent rotation and movement. Have some nail polish handy to repot them. They are VERY VERY difficult to remove without damage. This was by far the hardest part, yet, it is sort of just a "go slow and be careful not to damage anything" kind of instruction. You will need two fine, small yet not too narrow screwdrivers, and an exacto blade on a handle. You want to try to remove the pressure from each spoke of the keeper, while trying to pry up the ring at the same time. You HAVE to work your way around and around the ring with the exacto blade, a screwdriver will not go under, to get it off w/o mangling it. You will have to bend it back into shape in order reuse it and still provide enough holding force. When you install it, you need a small screwdriver and a LIGHT hammer (jewlers or equal) to tap each spoke, carefully, one at a time lightly, to get it tightly in place, while keeping the sensor in the correct orientation.

8. Removing the idler hub, he emphasizes being very careful. He's not kidding. Tiny E circlips are ALWAYS a PITA, and this one is no different. ALWAYS put a long piece of cellophane tape over the hub, then pierce it with your tiny screwdriver of choice to remove the circlip, assuming you don't have a removal tool (who does). This will keep the spring on top of the hub from launching the circlip, two washers and the spring across the room. Reinstall the same way. Install the spring correctly, then the large and small washer, and then retain in place with a long strip of cellophane tape, that you pierce the shaft through with. Then use a small needle nose to carefully snap the circlip back in its groove. The tape is easy to remove after. Try to do it w/o the tape and you will lose parts.

9. He instructs to put the mechanism back in place and THEN remove the NAAC assembly. I can think of no reason for this. Remove the NAAC after you get the halves back together. Much easier. I also found it easier to remove the NAAC motor as well as the positioning part when snapping the shaft up out of the keeper to remove the belt. It comes out quite easily, and that was the part I thought would have been the most difficult. It wasn't. What he doesn't mention, is that the NAAC large pully will slide on it's shaft when you pop the shaft up, it's just a friction fit. Be sure to realign the large pully with the motor pully, after you get it all back together. The motor and postioner screws are also potted in place, Nail polish again. I also found it easier to do this with the NAAC bowden cable unsnapped from the NAAC unit. It pops off easily, but reinstalling it is a little tricky, as it is spring loaded, and you need to use a fine blade to center the bowden driven part into the center of the NAAC positioner.

These are all just from memory, so I may have to amend them a little after I review it, again. Feel free to PM me with any questions, offer suggestions or ask for clarifications.

[Nakdoc]

An important note on step #6. Do not pull the capstan 1/2 way out and let it hang. You risk bending the capstan!

After talking to Perry I decided to track down some IT-6 idler tires, and it appears to be a difficult task. If you are interested and have a local TV repair place in town, pay them a visit and buy their remaining supply. TV shops bought kits with 10 tires of each size. the IT-6 crosses to RCA 144265, Panasonic VXP0213,VXP0243

[Dragonbreath]

so perry how long did this take again?

[perry]

As you may guess, I try to be uber careful, so I take longer. This was my first Dragon rework. To get from play to play, was about 8 hours, over 2 days. I had to wait a few days for the new idler tyre to arrive, after I discovered mine was defective. It takes about 2 hours just to put it all back together. Now that I've done one, I could probably do another in 6 hours. For comparison, a total rebelt on my RX-505s (without the idlers!, so no cassette mechanism removal, took me about 4 hours the first time, and I can do it in about 2 now. You can do al the belts w/o cassette mech disassembly, but the flip and drawer belts are a PITA on their own. I am heeding Nacdocs advice and leaving the 505 tyres alone, as they make no noise, and every tyre related function works properly.

EDIT: I spent 2 hours Friday night installing the sockets for the ANT4066 upgrade, and power level translation. Very clean install compared to the B215, just because the layout of the board is conducive to it. However, it is a bit tight to work with as I did not want to disconnect everything and remove the board, so I worked it with the board about 4 inches away from chassis. Then I spent 4 hours Sat night doing head alignment and testing of different tapes. What a difference. Like others that work on decks, you think, "Wow, this is great sounding deck", then you align everything, and you are speechless. I don't know what to say, but I'm floored. This must be what Angel has been talking about, and since ESL does much more than I can, they must be truly amazing decks. I can't wait to check out my 505s, now that I have it somewhat down. The problem that I had with the UDXL tape only calibrating when the heads were spotlessly clean was record head azimuth (DUH, seems obvious now). I noticed I had a similar issue getting the new UX-Pros I got from Larry to cal, so I was worried it might be a deck issue. I was SO amazed how a small amount of azimuth screw turn, (less than 90 degrees), made. The signal literally pegged the meter on my Leader LAS-5500 audio analyzer. I went back and forth, checking and rechecking with reference and cal tapes, then I dropped in a new (gulp) MA-R, and ran the FR test. JUST FREAKING AMAZING. EASILY flat from 20 - 22K Hz within 2 db, dolby C, at 0db input. I almost cried, it was so beautiful. See my other post on "Testing tapes with calibrated Dragon" for more.

[kawzx7]

Thanks Nacdoc, you da man! Sort of academic now, as I opened her up last night to lube the cam shaft (which eliminated the screech, just like on the 505s) and all the belts are pretty floppy/loose, but work as required. The idler tyre has slight visible checking on it, as well, so I've ordered a rebelt kit. Plays beautifully tho, and the NAAC works perfectly. Very pleased for a bit over $400. Plus, a nice high serial number, 245XX, can't remember the last two digits. Spotless inside. Here are few shots of the business end of the belts and the heads. Pinches need a good cleaning, but rotate freely, as do the spring loaded tape guides. A very slight tick-tick in the supply reel side, (may be nothing, have to investigate, as it seemed to change depending on tape used), and curiously if you put your ear right up to the opened door, there is a definite audible motor hum, can't be heard 6 inches away though..normal?

I know this is old, but Perry, did you ever find the source of the tick tick and the audible motor hum?

[perry]

Yes, it was the idler tire arm. It was not square to the motor pulley, so it ran sort of on the corner of the tire. I replaced it (I bought a few in Feb of this year during a MASSIVE ebay auction of a ton of Nak parts from a shut down repair facility) and it solved the issue. The hum was shielding on the transformer. ESL shields theirs, and I bought a few sheets of MU metal (thanks, Mike) and when I shielded mine, "POOF" , no more hum. Odd, though, my other Dragons have no such hum, even without shielding.

[studeb]

i am confused

How does mu metal stop the audible hum through the door? If it was EMI type hum coming through your system that would make sense. Do you think it is just acoustic damping that it is doing?

Yes, The hum was shielding on the transformer. ESL shields theirs, and I bought a few sheets of MU metal (thanks, Mike) and when I shielded mine, "POOF" , no more hum. Odd, though, my other Dragons have no such hum, even without shielding.