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A Solution To Blankdisc And Recording Problems.

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14 hours ago, SilverGreen93 said:

Only the records have drops and the MD stalls when trying to access the recording for playback on certain points.

I'm working from home with the current situation and in the background dubbing a lot of CDs to MD for when we return to the office (I have my MZ-R700 there). I'm having similar issues occasionally happen with my Tascam MD-CD1. Some discs are dropping out at least once per track, some not at all. If I re-record I can get the drop-outs but at a different position. I've tried brand new discs (old stock) discs from Sony, TDK, Maxell etc plus erased/previously recorded of same. The skip position moves. (The CD I'm dubbing from is not scratched/skipping at that point). I've yet to track this down to a definitive reason. I've been using SP and LP2 and SP is the most common but it does happen on occasion on LP2. I thought at one point the Type-R encoder might have a fault - I don't believe LP2 is Type-R - although this might only be with 2x/4x dub? Also I have it with both real-time dub and high speed (2x, 4x dub) - again at one point I thought it was a high speed dub issue.

Anyway, all to say, I think I have a similar issue on a totally unrelated machine (although the MD-CD1 is based on the Sony CXD2662 chipset). Interestingly, MZ-R700 I think is of a similar generation (MDLP but not Type-S) - not the "fullsize" CXD2662 but the walkman version thereof...

Kevin

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sounds mechanical to me. nothing to do with type r which is mainly for real recordings ie doesn't come into play with high speed dubs. the drops are probably when there's extreme movement laterally of the head (sled). could be laser power, but i have seen this most often on netmd transfers with borderline battery for power. Doesn't happen on netmd when unit's HiMD

with your observational skills you can probably correlate the drops with head movement.. requires cover off the mdm7 disk drive

 

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23 minutes ago, sfbp said:

sounds mechanical to me

I'm sure you're right. It's done a lot of work recently - and the past week I've not found this happening. It's not an MDM7, it's a Tascam drive, but based on the Sony chipset. It might be in need of a very tiny amount of lubrication (Molykote EM-30L) as you say.

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On 5/10/2020 at 11:15 PM, sfbp said:

Sounds like an adjust and/or lube job to me. The less resistance, the less battery used, too - as I found out with my E909. Of all my gumstick-driven units, it's the one that seems to have the most play time - seems to me that I might have cleaned up its extremely delicate mechanism as a prerequisite to reviving it. The ones which grind a lot probably do need the old lube job and/or disassembly and much fiddling to minimise mechanical resistance.

All said and done, unless this only happens when on battery, you've likely got a little bit of electrical adjusting to do. My experience is that the first couple of power adjustments are the ones which really matter. Getting more juice (volts) to the circuit affects everything including whether knobs respond correctly (changing resistance on knob-press) and whether the laser ultimately gets enough power. However,,,,, once the rails are up to the voltage they should be (and running off the wall should allow you to eliminate that problem) if there are still dropouts then the laser needs a re-adjustment. For non-HiMD it's not that complicated. Basically stick in a blank disk and it does its thing. You'll need 1 prerecorded MD (CD) though.

I disassembled today my R700 and cleaned it all thoroughly, lubed the shafts of the laser assembly, cleaned the laser and write head with IPA.

I inspected and measured the ribbon of the write head and it is is all intact.

After putting it all together, the same issue can be seen. Plays perfectly, but records only fragments of the sound...

What adjustments should I try to make? I have the service manual, I tried increasing the tracking gain by a little and the power of the laser on write mode but there is no difference.

Toc edit still works fine...

Can you point me some important adjustments that i need to look into? I think it can be fixed.

Edit: Can be a write head misalignment issue with the laser? Although I believe not, as I do not see how it can get misaligned

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Ok well done with that - certainly can't hurt. My own experience with the featherweight E909 was that I had to fiddle with it several times to get it back together perfectly, but when I did, the (resulting?) lack of mechanical resistance means that the battery lasts forever, as it should with that model.

I think maybe time to do some adjustment. You'll mainly need a regulated powersupply capable of sourcing exactly 1.2 volts (the minimum acceptable voltage for gumsticks).Once you have all the electrical checks done, then you can try the self-alignment routine, if that didn't make the difference.

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On 5/25/2020 at 10:54 PM, sfbp said:

Ok well done with that - certainly can't hurt. My own experience with the featherweight E909 was that I had to fiddle with it several times to get it back together perfectly, but when I did, the (resulting?) lack of mechanical resistance means that the battery lasts forever, as it should with that model.

I think maybe time to do some adjustment. You'll mainly need a regulated powersupply capable of sourcing exactly 1.2 volts (the minimum acceptable voltage for gumsticks).Once you have all the electrical checks done, then you can try the self-alignment routine, if that didn't make the difference.

I cleared the NVRAM, performed the electrical adjustments, item 764 (V1PWM) was 2.28V instead of 2.30V. I adjusted it successfully to 2.30V, but now I have a bigger problem. I cannot pass the automatic CD adjustment anymore, it gives me 324 NG 00   0 00 error, which from my understanding is traking error. The manual recommends to perform the laser check and set the LrefPw, HrefpW and WritPw, but I don't have any laser power meter to test the power. Also, the temperature compensation value that I set is always reset to default for whatever reason I don't get even if i press pause to save the values.

Bottom line: I cannot use my MD anymore, it now always enter test mode on powerup because the adjustements are not completed. Can you or anyone help me complete the adjustmnets to make it work again?

A thousand thanks!

Edit: How in the world should I measure the voltage drop on the R521 resistor during laser power adjustment when the resistor is just on the other side of the pdb when assembled toghether? Are they nuts for putting it on the other side?

Edit2: Can anyone with a MZ-R700 tell me the values for the above settings to get mine working again?

 

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Still sounds mechanical to me. The CD test is by far the least demanding, and if it fails (I assume you tried it before and it worked) there's something seriously wrong.

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7 minutes ago, sfbp said:

Still sounds mechanical to me. The CD test is by far the least demanding, and if it fails (I assume you tried it before and it worked) there's something seriously wrong.

Well, the self-calibration tests were working before I reset the nvram. I now need somehow to get the laser power back to normal to pass the tests, doesn't look mechanical to me.

Maybe the write was failing previously due to the low voltage on the laser and now after I get the calibration right it will work. The problem for the moment is that i cannot make sure the laser power is good to pass the self-calibration.

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"reset the NVRAM" is actually a misnomer. All they did, when you pushed the 911 emergency panic button was to reset a single byte in memory. Emphatically the NVRAM was not cleared. The laser power settings will not have been touched. All you did was to force a calibration.

My deduction is (FWIW, free advice is worth what you pay for it), you are having a similar issue to myself with the player I mentioned, that somehow things are not moving right. It turned out to be absolutely tiny variations in how I tightened the relevant screws when re-assembling.

 I'm curious, just how far did you strip it down?

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I took apart only the main pcb, did not diassemble the optical pickup, so far so I could reach the test points to measure the voltages and lubricate the mechanical parts and rails.

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Well for it to fail the CD test something is seriously wrong. I've almost never seen the CD test fail unless I mis-assembled it. YMMV, of course, no offence intended.

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Nope. That has nothing to do with the R700 (and related, contemporaneous models). By RXX I understand R35, R50 etc.

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