Sony EV-S7000 service manual with board schematics?
 

Hello all,

Wondering if anyone has a digital version of the full service manual for the EV-S7000 Hi8 deck with board schematics? There's what I believe to be a partial one on elektrotonya, but it does not contain any of the board schematics.

There are a few sellers on eBay that sell digital versions as well as hard copies, but I also don't know if those contain the board schematics either, or if they are a repackaged version of what's on elektrotonya.

Main reason for needing the schematics is that a lot of the adjustments aren't clearly marked on the PCB and seeing the board schematics would make it a lot easier as well as much easier to focus on certain areas when recapping if there's an audio versus video problem.

I'm quite curious to see if the playback is any better than standard D8 cameras that can play older tapes - many say that they prefer the picture from the EV-S7000, so it must have some different characteristics and I'll post some comparisons once my unit is tuned up. For now, the video levels are hotter than they should be, but it otherwise appears to be functional after a TBC recap.

Thanks in advance!

Attached is the adjusting parts location diagram, which should show the location on the boards of the adjustments if that helps.
The Printed Wiring Boards and Schematic Diagrams section runs ~106 pages.

Which boards did you recap? (the TBC board is not named as such)
Did you do just the SMD electrolytics, all electrolytics, or something else?
What were the symptoms that prompted recap?

As a minimum the EV-S7000 provided much better and more convenient tape handling than camcorders and players based on camcorder tape transports.

The MacroVision support can be disabled by removing the VP40 (MACRO) board.

Thanks for the info! I recapped the power supply (had obviously leaky caps), head amp (RP-165), and Digital Board (DI-51 - which was full of bad SMT caps). The Digital board only had two through-hole electrolytic capacitors, but I did change those as well.

In retrospect, the head amp probably didn't need recapping and I mainly did that because I didn't want to have to plug and unplug the fine ribbon cables from that more than I had to in the future and was already doing so when I refurbished the deck mechanism.

The issue I was mainly trying to address with calibrations and recap were:

1. AGC doesn't seem to actually work (will output greater than 100IRE signals if the tape was recorded that way, doesn't matter if TBC is enabled or not.

2. Output chroma levels are reduced by 20-30% looking at a vectorscope both on passthrough (feeding color bars from test pattern generator and hooking a vector scope up to the video output of the unit - both S-Video and Composite have the issue) as well as during playback of a color bar test tape. Oddly, luma levels seem unchanged and fine on both passthrough and playback.


Basically what I've found is that RV200 and RV700 affect luma levels during playback (only when TBC is enabled) and only in a fixed way, so reducing them for a "hot" signal tape also lowers luma levels for appropriately recorded tapes. RV112 only affects chroma level during playback and not passthrough and adjustment procedure for that is supposed to make chroma match whether edit mode is on or off, so it is clearly not supposed to be used to correct passthrough or playback levels.

I'm pretty sure that whatever is causing my passthrough chroma levels to be low is why my chroma is equally low when playing back a color bar test tape as well, so I'd really like to get that figured out first. The only parts during the video calibration procedure that address chroma levels is looking at the burst level, and I have verified that to be correct, and even just adjusting that variable resistor further doesn't change passthrough or playback output chroma levels.

I will say I haven't messed with TU-145 which has something labeled "AGC" as it is not referenced in the partial service manual I have, though I don't think that's probably what is causing my passthrough and playback and output chroma levels to be consistently low. Could be starting there would have saved me a lot of hassle, but I also don't have the adjustment procedure for that.

Any ideas on where to go from here? Any help is much appreciated!

Thanks for the note of the DI-51 (digital process) board, I suspect it is the issue with my VCR.

TU-145 board is the tuner and the AGC on it is for RF signals fed to the unit (e.g., off the air recording).

Video AGC may key off sync height, not video peak, so it can pass more than 100 IRE luma.

RV602 on the VI-121 board might address the C levels for playback and pass thru and RV601 the Y levels. (Manual steps 2.5.4 % 2.5.3.)

Will have to open my "7000" next week to checks its guts.

I'd be curious to see if your unit's chroma output matches the input during passthrough or not - could be this is a common issue that doesn't really get tested since you basically need a vectorscope or oscilloscope and a pattern generator to see it properly. Oscilloscope is harder to really discern unless you have a way to tap into the chroma line on the S-Video cable on both the input and output and compare them on the same screen. The picture it gives looks ok for real world tape playback, but I'd prefer that 20-30% of the chroma didn't just go away when passing through or playing back.

You might be right about AGC being triggered off of the sync height - which would be unfortunate since sync heights can vary quite a bit from tape to tape I think and different cameras tend to record at different levels. Not too unlike how VHS can be, seems quite common for commercial tapes to output as high as 130 or more IRE (even excluding the macrovision signals), possibly to mess with re-recordings.

RV602 can be used to bring up the overall chroma level of composite to match the input - but S-Video is completely unaffected. If you actually raise that up enough to get the inputs to match, the total height of the color burst is something like 50% higher than it should be according to the calibration steps though. I think what happens when that is done is that it compensates for the later reduction in chroma by whatever component is squashing it. S-Video is probably unaffected because its chroma is unprocessed since it's already separate when it makes it into the machine and there'd be no reason to have to amplify it for passthrough purposes.



My thought at this point is that there must be an extra resistance somewhere in the chroma line that is common to both the playback and passthrough chains since they both have reduced chroma by the same amount. I could see it being either a resistance coupled to ground, or an inline capacitor with a high ESR maybe? Perhaps that "series resistance" is all it would take to reduce the chroma if the capacitor was inline. I'd have to see the board schematics to get an idea, but even then it's beyond me to electrically narrow it down. Would be a lot easier if I had a machine that didn't have that issue that I could compare different test points along the signal path to look for differences.

I've never really messed with "freeze spray", but part of me wants to spray different capacitors to see if the chroma reduction gets even worse with specific capacitors being cold and that might narrow it down.... but that sounds too easy haha. Or I could be barking up the wrong tree altogether, so still quite open to other suggestions on how to chase the chroma reduction problem down. AGC I guess is less of an issue.

My EV-S7000 is NTSC, has had no components changed, and dates to the mid 1990s.

I did a quick check with color bars and a stepped gray scale from a GEKCO VG-10 signal generator

I did a capture of the of the bars & scale direct from the VG10 and passed through the EV-S7000, viewed the captures with the vector scope in my NLE.

The IRE values were perhaps 2-3% lower with the pass thru (no significant loss) and the effect on luma and chroma levels was the same. Colors pass thru was accurate based on the vector scope, no significant change in hue.

However, there was substantial noise visible added to the pass thru signal, both luma and chroma, possibly the result of failing caps. Something I will investigate in the near future. It looks like the only SMD electrolytic caps are on the DI-51 board, about 30 of them.

DNR only works if the TBC is active and I suspect the TBC is for playback, not pass thru or recording.

Yeah, my signals are extremely clean during passthrough after the recap, there's just that 20%+ chroma reduction on both playback and passthrough. Really seems like a resistor (or something acting like one) is pulling the signal down. I've messed with just about every VR in the machine and nothing seems to affect both the playback level and the input level. I guess 20% might be an exaggeration, I can't remember what the "larger target boxes" are for chroma on this WFM90. You might think that's looking at a 100% targets instead of 75%, but when I plug the color bar generator directly into the WFM90, it hits all of the targets correctly with 75% SMPTE bars.

Attachment 18412

There is a "picture adjust" that you can use in the settings to amplify the color during playback which I suppose would compensate for it, but I feel that will just add more noise than having native passthrough and playback levels be correct.

I guess if the color burst level was "too high" on the output, that could cause the same result? Hmm.

Really wish I'd have checked passthrough levels before I refurbished it to see if it was that way before the recap or not.

Guess I should just be thankful that my supply/take up reel gears are not cracked - seems most of them do crack (and there are no replacements available) and it'll make terrible noises when fast forwarding or rewinding if that's the case.

One other thing - according to the schematics, what kind of batteries does this use for the clock and settings? Almost looked like there was on the main PCB as well as a different battery on the lower slide out drawer area.

The only batteries I am aware of are the AAs in the remote control.

Setting are saved in EEPROM memory.

Mine loses the c lock set time if power is lost for more than a minute or two.

I wonder if there is a "super capacitor" aka "ultra capacitor" used to keep the time alive during power interruptions? I don't see one on the parts list but I have replaced a couple in old stereo receivers.

I checked the ESR on a few caps on the DI-51 board "in circuit" and the SMDs appear to be high while the two NPs appear to be OK. looks like 31 SMDs needed for a recap of the board.

I'm not sure if it's just the clock or not. Seems if you turn the TBC off for example that it also gets reset to being on after unplugging. I'll be curious if after you recap your DI51 board if the output chroma level will change. I kind of doubt the issue is there since there's really no reason that the passthrough signals would have to go through the TBC board unless the TBC in there can be used as a passthrough device, which I've never seen on any VHS VCR anyway. It also does not matter if the TBC is enabled or not and the chroma is still low.

I did reach out to Dr. Sony who sells refurbished units on ebay and he notes they have a calibration service that I might look into. It's just kind of lame that I have all the tools other than calibration tapes which I'm pretty certain this is not related to since passthrough is independent of the deck mechanism (and playback does it to the same degree as passthrough). I'm sure if I paid for the service and received it back and the chroma issue was still there, there wouldn't be any recourse, or they might try to tack on some other refurbishing service that I don't really need after having already replaced the high failure rate components. I am fairly certain this is due to a single component misbehaving (adding a fixed resistance) either inline on the chroma signal or coupled from the signal to ground based on what it is doing.

Video99.uk has some videos on repairing his EV-S9000 units which are basically the PAL variant of the EV-S7000 and his had tons of bad caps on the main boards. I'm kind of wondering if those used different capacitor brands though, because just about everything in my unit are Nichicon caps.

I'll probably spring for the digital service manual on ebay next, but an original printed one would be much better since I know that would be complete.

For your manual, is the schematic part of the regular service manual, or is it an add on with a separate part number/title?

The schematic diagrams, board layouts, block diagrams are on fold-out pages, many as large as 16.5 x 34 inches. Some boards cover more than one page. Some pages have more than one board on them. They represent roughly 2/3 of the manual thickness. They are not a separate booklet. The full printed manual page cound per the ToC exceeds 230 pages. (Fold-outs count as multiple mages.)

Per the user manual the "initial setting" for TBC is ON, so a power loss that is more than a brief flicker may well result in it being reset.