Just a quick tip to those using the JVC transport as standard (i.e. with the puck). You get a slight increase (OK then, I guess this falls under the 'perceived' banner 
) in quality by taking the magnetic out of the puck, applying a tin layer of cork (or rubber mat) to the underside to protect from scratching the CDs, and reducing the magnetic 'pull' slightly by creating a slight gap between magnet and CD. No more oscillation, and - I think - this means less work for the servos/error correction circuits, which MAY result in an increase in sound quality.
Worth a try at any rate - it's free
) in quality by taking the magnetic out of the puck, applying a tin layer of cork (or rubber mat) to the underside to protect from scratching the CDs, and reducing the magnetic 'pull' slightly by creating a slight gap between magnet and CD. No more oscillation, and - I think - this means less work for the servos/error correction circuits, which MAY result in an increase in sound quality.Worth a try at any rate - it's free
Ace is the place?
The Ace hardware store's selection of springs was numerous, just not right. I also saw that any spring in the size range of interest would be ~$3-4 each.
I'll chip in for a dozen or more of the McMaster-Carr #9657K101.
Would any of you be interested in 4?..this is a one-time offer, pm me if so.
I'll let this idea run for a few days before I place the order....shhhh...be verwy, verwy qwiet, don't want to provoke the moderators into moving this into the marketplace.
As to the use of o-rings: I'll use them as tensioners. I'll look for the x-section, length and number needed to compress the springs in order to kill resonances.
The Ace hardware store's selection of springs was numerous, just not right. I also saw that any spring in the size range of interest would be ~$3-4 each.
I'll chip in for a dozen or more of the McMaster-Carr #9657K101.
Would any of you be interested in 4?..this is a one-time offer, pm me if so.
I'll let this idea run for a few days before I place the order....shhhh...be verwy, verwy qwiet, don't want to provoke the moderators into moving this into the marketplace.
As to the use of o-rings: I'll use them as tensioners. I'll look for the x-section, length and number needed to compress the springs in order to kill resonances.
Re: shigaclone
Quan:
The board is single layer, and yes a connection to C952 (Not C902 which should be a small smd cap totally unrelated to power.) should work fine. You haven't explained why the cap burned - did you put more than 10V power into the board? (C952 is only rated for 10V, with derating should not see more than 8V on a continuous basis for reliability.
Johnm:
I think my RCEZ32 based clone significantly outperforms my media server in some ways. It seems generally a touch more refined - nothing earth shattering as the server is quite good, and the differences aren't immediately apparent in casual listening. I think one particular area where the clone really seems to stand out is in the frequency extremes, the bottom octaves are extremely well defined, controlled and convincing, and in the very top octaves this is some of the cleanest "undigital" sound I have heard from cd.
quan said:Hi guys, need help -again ,accidentally i destroyed the pad for positive 8v in -position -old choke was removed-was using a drill to widen the hole but went too far thus stripped all pad!!
How do i go about fixing the problem.
Could direct connection to C902 work?
Quan:
The board is single layer, and yes a connection to C952 (Not C902 which should be a small smd cap totally unrelated to power.) should work fine. You haven't explained why the cap burned - did you put more than 10V power into the board? (C952 is only rated for 10V, with derating should not see more than 8V on a continuous basis for reliability.
Johnm:
I think my RCEZ32 based clone significantly outperforms my media server in some ways. It seems generally a touch more refined - nothing earth shattering as the server is quite good, and the differences aren't immediately apparent in casual listening. I think one particular area where the clone really seems to stand out is in the frequency extremes, the bottom octaves are extremely well defined, controlled and convincing, and in the very top octaves this is some of the cleanest "undigital" sound I have heard from cd.
I think so. Please note this spring is depicted as having a closed, but not ground, end. This means it will not rest upright on a flat surface. If you can accommodate that into your build, you should be fine. This says nothing about the balance between the spring rate and the weight of plinth upon it.
An externally hosted image should be here but it was not working when we last tested it.
The spring referenced earlier from McMaster-Carr has closed as well as ground ends. See below.
An externally hosted image should be here but it was not working when we last tested it.
balance
For the last couple of hours I should have been mindful of other things. As it was, I remained distracted with thoughts about the plinth. This is only a concept, I welcome comments and suggestions.
I see the plinth carrying the cd drive and laser mechanism. The plinth is made from a dense wood like hard maple, up to 2" thick. I see the springs countersunk into ~1" diameter holes near the corners of the plinth. It is likely rectangular in plan view. The countersinks are not equidistant from the corners of the plinth. Close, but offset just a little.
My mention of o-rings earlier (shoot, they could be rubber bands, just more of them) includes them being angled from vertical. Equal numbers of them in opposition to lend torsional stability to the mix. The points of attachment and number of them to be determined as the assembly becomes complete.
The sub-base for all of this receives the bottoms of the springs and provides the lower points of attachment for the tensioners. It is at least 1/2" thick baltic birch with slotted holes to allow adjusting it's position within the case. luvdunhill suggested the use of die spring screw caps for holding the ends of the springs. See below. Something like that will be needed.
We all know what happens to rubber bands over time. Their use can provide a solution for a time, I think. My thoughts for o-rings anticipates their longer lifespan.
For the last couple of hours I should have been mindful of other things. As it was, I remained distracted with thoughts about the plinth. This is only a concept, I welcome comments and suggestions.
I see the plinth carrying the cd drive and laser mechanism. The plinth is made from a dense wood like hard maple, up to 2" thick. I see the springs countersunk into ~1" diameter holes near the corners of the plinth. It is likely rectangular in plan view. The countersinks are not equidistant from the corners of the plinth. Close, but offset just a little.
My mention of o-rings earlier (shoot, they could be rubber bands, just more of them) includes them being angled from vertical. Equal numbers of them in opposition to lend torsional stability to the mix. The points of attachment and number of them to be determined as the assembly becomes complete.
The sub-base for all of this receives the bottoms of the springs and provides the lower points of attachment for the tensioners. It is at least 1/2" thick baltic birch with slotted holes to allow adjusting it's position within the case. luvdunhill suggested the use of die spring screw caps for holding the ends of the springs. See below. Something like that will be needed.
An externally hosted image should be here but it was not working when we last tested it.
We all know what happens to rubber bands over time. Their use can provide a solution for a time, I think. My thoughts for o-rings anticipates their longer lifespan.
Ed LaFontaine said:
Correct. This is something to consider. Thanks for advise
About the O rings honestly I cant´t figure how they go with springs assembly since I didn´t see a pic so far in this thread. No rubber bands at all, they won´t last six months.
Time to bed now
Thanks again and later
shigaclone
Thanks Kevin for the reply,
i have tried to connect the PS thru C952 which meant to removed anyway from RC-EZ31.
The problem is that- no power onto the transport board, the C902 which i think is a voltage regulator gets very hot and then smoke. It is not the cap that smoke.
The other thing that i noted as well that the transformer from the power supply start to hum or oscillate?.
Where should i check next?.
Thanks Kevin for the reply,
i have tried to connect the PS thru C952 which meant to removed anyway from RC-EZ31.
The problem is that- no power onto the transport board, the C902 which i think is a voltage regulator gets very hot and then smoke. It is not the cap that smoke.
The other thing that i noted as well that the transformer from the power supply start to hum or oscillate?.
Where should i check next?.
Good Morning form here
Take a look at Peter's post #868 & 869:
Peter's photo of Levinson
Don't look for a specific example of this in the thread...we are building this in my head for now...
Where Peter has used the mass of metal to load the springs in his suspension, I am suggesting the use of "tensioners". The tension springs in post 869 are an example of this.
The o-rings are used as tensioners. An o-ring is hooked onto a point of attachment on the plinth and then stretched gently to another point on the sub-base. This tension compresses the springs slightly. Each additional o-ring increases the compression of the springs. The compression of the springs is balanced against the tension in the o-rings along with the weight of the plinth.
I think I'll start with 2 o-rings on all 4 sides of the plinth, 1 on each side of a corner, 8 o-rings.
Hi all,
I don't know if I imagine all this or if it is real. I have the pdf document of Okapi and there is no type of cap for the transport board. I think I saw somewere a list of component with the type of all caps, not just the PSU. Can someone point me to the document/post, I cannot find it,
Thanks
I don't know if I imagine all this or if it is real. I have the pdf document of Okapi and there is no type of cap for the transport board. I think I saw somewere a list of component with the type of all caps, not just the PSU. Can someone point me to the document/post, I cannot find it,
Thanks
Re: shigaclone
Hi Quan,
I think you have mis-identified C902, it is a cap associated the ASP chip. Did you connect the power up backwards by some chance? If any chip smoked it is likely you will need to look for another boom box. You might be able to find replacements but I don't know how likely that is.
quan said:
Hi Quan,
I think you have mis-identified C902, it is a cap associated the ASP chip. Did you connect the power up backwards by some chance? If any chip smoked it is likely you will need to look for another boom box. You might be able to find replacements but I don't know how likely that is.
Hi Quan,
I hope you did not mean IC902 because if that is the chip that smoked it is a clear indication that you made a serious wiring error and this board set is history unless you can get all of the chips IC901, 902, and 903 and identify all of the many other components that will need to be replaced as well. (The laser and photo diodes may also be damaged - so I would replace the whole thing.)
The fact that the power transformer buzzes loudly when connected is a strong indication that something has shorted out.
Do you have a meter? Can you measure the 8V supply, after carefully rechecking everything.. Incidentally I recommend soldering the wires on the bottom side of the pcb at C952. I don't recommed drilling any holes out as no one (myself included) other than Peter seems to be very adept at this.
Sorry to be a bearer of bad news, but this does not sound good.
FWIW I toasted the first micro-controller board in my RCEZ32 based version so I know what angst you must be feeling right now. Purchasing another one of these rather rare boom boxes was the only option in my case.
I hope you did not mean IC902 because if that is the chip that smoked it is a clear indication that you made a serious wiring error and this board set is history unless you can get all of the chips IC901, 902, and 903 and identify all of the many other components that will need to be replaced as well. (The laser and photo diodes may also be damaged - so I would replace the whole thing.)
The fact that the power transformer buzzes loudly when connected is a strong indication that something has shorted out.
Do you have a meter? Can you measure the 8V supply, after carefully rechecking everything.. Incidentally I recommend soldering the wires on the bottom side of the pcb at C952. I don't recommed drilling any holes out as no one (myself included) other than Peter seems to be very adept at this.
Sorry to be a bearer of bad news, but this does not sound good.
FWIW I toasted the first micro-controller board in my RCEZ32 based version so I know what angst you must be feeling right now. Purchasing another one of these rather rare boom boxes was the only option in my case.
Having applied too high voltage to the transport myself, I might offer a small glimmer of hope. Kevin is right in that if the voltage was applied backwards, there might not be hope. But I applied about 14 volts and the 10 v electrolyitc went, and the supply itself went (or was already bad), but the rest of the transport survived. The motor driver chip is rated about 14 volts with internal regulator. The rest of the chips on the 32 have regulators in front of them. Now those transistors may be fried, but the chips themselves may have survived.
Since you have a 31 and the service manual has been posted, it would be worth checking against the regulation in the schematic before tossing the transport to see if only the regulation was damaged.
But I do agree with Kevin. First step is to ensure you have a properly functioning power supply indepedent of the transport. I was able to fit short power wires into the holes that used to hold the inductor, but checked way too many times to ensure I did not hook them up backwards.
Good luck in your trials.
Craig
Since you have a 31 and the service manual has been posted, it would be worth checking against the regulation in the schematic before tossing the transport to see if only the regulation was damaged.
But I do agree with Kevin. First step is to ensure you have a properly functioning power supply indepedent of the transport. I was able to fit short power wires into the holes that used to hold the inductor, but checked way too many times to ensure I did not hook them up backwards.
Good luck in your trials.
Craig
Hi Franz,
I'm curious to your findings. It seems that the Studer is using a CDM 4 variant.
I haven't had time to do any further mods to my JVC. Just some of my findings regarding the puck/clamp:
When playing with the Philips transports a friend and I found that the mass of the CD puck has an effect on the sound, we used blu-tac and washers to experiment, finding that the optimum mass was about 40 grams . I had an engineer machine a brass disc to about 42 grams which I glued to the original Philips clamp (lead mass removed). It worked well, the most important thing was that everything was correctly centred, this drastically reduced any vibrations.
I haven't implemented anything like this on the JVC yet, but lowering the centre of gravity of the clamp/puck may also be of benefit.
Happy modding
Richard
I'm curious to your findings. It seems that the Studer is using a CDM 4 variant.
I haven't had time to do any further mods to my JVC. Just some of my findings regarding the puck/clamp:
When playing with the Philips transports a friend and I found that the mass of the CD puck has an effect on the sound, we used blu-tac and washers to experiment, finding that the optimum mass was about 40 grams . I had an engineer machine a brass disc to about 42 grams which I glued to the original Philips clamp (lead mass removed). It worked well, the most important thing was that everything was correctly centred, this drastically reduced any vibrations.
I haven't implemented anything like this on the JVC yet, but lowering the centre of gravity of the clamp/puck may also be of benefit.
Happy modding
Richard
I have a small trace that is popping up. Any recommendations on something to "glue" it back to the board?
Also, FWIW I have had luck enlarging the holes using a 1/16" bit placed into a tapping chuck and then using it by hand. I've enlarged a number of holes on this board using this trick. I'm still not confident enough to try and accesss the DOUT pin directly though.
Also, FWIW I have had luck enlarging the holes using a 1/16" bit placed into a tapping chuck and then using it by hand. I've enlarged a number of holes on this board using this trick. I'm still not confident enough to try and accesss the DOUT pin directly though.
luvdunhill said:
luvdunhill,
One trick I use in such circumstance is this:
1) get a magnifying glass from a watchman/clockman repair guy
2) get good lighting conditions
3) use a sewing needle
4) scratch delicately until you reach the metal
Alternatively, get the schematics, find where the line goes to the next submerging trace, then solder your component's other leg there.
I had that unpleasant experience several times, but managed to get by. If you have a component leg extending over a lot of other exposed components, use some isolation tubing to cover and isolate that leg. Very cheap stuff and always useful.
Hope this helps!