woolsey@nsc.nsc.com (Jeff Woolsey) (02/08/88)
It's about time that I brought people up to date on things I've been doing relevant to what they once expressed an interest in. These articles are abridged. In article SIMTEL20.WANCHO.12323837931.BABYL in rec.video dated 4 Aug 87 17:03:00 GMT, WANCHO@SIMTEL20.ARPA ("Frank J. Wancho") writes about SONY Service Manuals: > Based on the comments seen here about the SONY manuals, a desire >to see what's really going on with BIs and BIs SHB, and to get some >clues on how to repair the remote controls, I ordered and shortly >rerceived the manuals for the equipment I have, and the one for the >SL-HF1000 for comparison with the SL-HF900. > In my side-by-side comparison of the playback circuits of the two >units, I have yet to find the specific component value differences >and/or additional circuitry to account for the different handling of >BI vs. BIs, vs. BIs SHB. The SL-HF900 can play back BI only, whereas >the SL-HF1000 can play back all three formats (and record only the >latter two). I'd be interested in seeing direct replies from anyone >who has successfully made a similar comparison with the object of >modifying the SL-HL900 to properly play back BIs SHB tapes... In article <4189@utcsri.UUCP> in rec.video dated 23 Feb 87 00:49:12 GMT, pete@utcsri.UUCP (P. Schoeler) writes about Beta1 and XBR: >Here is the scoop on Beta recording speeds. > Speed Models with it Notes > BIs SL-HF1000(r&pb when "shb" switch is OFF) > SL-HF750(r&pb) > SL-HF650(pb only) > SL-HF450(pb only) > SL-HF900 Japanese Model(r&pb) > BI All Sony Consumer VCRs can playback BI, but > BIs and BIs.shb tapes "will be slightly degraded." > None (not even the 1000) can record BI. >Notes on the 900 > The US/Canadian version of this vcr is unable to playback BIs tapes. > The above statement was made by a SONY spokesman, and confirmed by > new product literature from SONY. (It could still be lies.) >Good Luck. > Stephen Trutiak > utcsri!alias!strutiak In article moscom.1022 in rec.video dated 27 Jul 87 12:20:33 GMT, adp@moscom.UUCP (Alan Percy) writes about HF900 recording at Beta I?: >A while ago someone mentioned that the Sony HF900 was capable of, with >modification, recording in Beta I mode. I sent for a set of service >manuals for the HF900 and can it be as simple adding another position >to the record speed switch!?!? Four wires run to the switch according >to the schematic (Beta I,II,III and return). >If someone posted an article on the required modifications, would you >please either repost it or E-mail it to me. Thanx! In article Xerox.870713-090540-1646 in rec.video dated 13 Jul 87 16:01:45 GMT, "Larry_Hudson.XSIS"@XEROX.COM writes about Re: SL-HF900 vs. SL-HF1000: >I have a 900 (only one unfortunately) and heard the SuperBeta Is rumor >some time ago. >"There ain't no such mod. -- at least by SONY." >I would be interested if you find out that somehow this rumor has some >truth to it. And finally, I posted the following at about the same time: >Newsgroups: rec.video >Subject: Beta I recording on SL-HF900 >Summary: almost >Armed with a service manual and an oscilloscope, I checked out just how >close the US/Canadian and Japanese versions of the SL-HF900 really >are. Other articles implied that the Japanese version was capable of >Beta Is recording. The US/Canadian service manual directs the >technician to make Beta I recordings. (Probably lifted verbatim from >the Japanese manual.) Well, with a little futzing, the US version is >almost capable of Beta Is recording, too. Here's how far I got this >afternoon. [description omitted since I supply better detail below] >So, before I go back over the service manual looking for the remaining >magic, or prove that it's missing, I'd like to hear from anyone else >who has been down this road before. >I also hope that nobody needs to be told that this is the sort of >behavior that voids warranties and possibly even service contracts. >Caveat hackor. =========== With all that behind us, here's what I've done to my SL-HF900 so far. I. Beta Is (monochrome :-( ) recording. 1) allow user to select Beta I speed: (implement schematic from service manual) a) remove front panel (top + 3 screws, clips @ edges) b) remove FR-14 board. remove REC MODE switch. discard plastic stop. reinstall switch. c) connect junction of R19 & R20 to switch lug nearest it / furthest from sparse end of switch. [ * O O O ] d) enlarge hole in front panel to accomodate full travel. e) reinstall FR-14 board and front panel. f) Check display for BI indication when switch is in leftmost position. 2) fix tracking. On the SL-HF900, Beta I record tracking is 180 degrees out of phase with everything else. This is accomplished with an XOR gate. Here we disable it. a) remove bottom panel (about a dozen screws). Locate SS-53 board. b) Isolate and ground pin 9 of IC519 on SS-53 board. Ground is available at pin 7. c) reinstall bottom panel. 3) restore chroma. Yeah, well. Good question. The video block diagram in the service manual shows a gain switch in the REC CHROMA path controlled by the Beta I signal. It's labelled Q659. The schematic for the VI-10 board does not show Q659. The VI-10 board foil diagram does not label Q659, but the traces are there. The VI-10 board itself does label Q659. Nothing in the SL-HF900 service manual identifies its part number or even its polarity. Never fear, however. The SL-HF860D service manual does show the Beta I gain switch in the VI-35 board schematic. (Same REC CHROMA circuit.) Use the transistor from the BIs playback mod (below) and a 2.2K ohm resistor. Install them at Q659 and R671. Then discover that the Beta Is chroma gain is now less than Beta II, and that the playback picture is still monochrome. The SL-HF1000 is substantially more complicated, having PEAK ACC DET and PEAK ACC AMP circuitry in the REC CHROMA path, and an integrated circuit for Y/C MIX (there's a BISHB-controlled GAIN SW in the IC). I'm open to suggestions at this point. II. Beta Is playback. 1) Prevent Beta I de-emphasis selection. a) remove bottom panel (all those screws again) and locate VI-10 board. b) remove Q710. Save it for the BIs color recording experiment. c) reinstall bottom panel. Note: This renders the SL-HF900 incapable of properly playing back Beta I (not Is) tapes (but how many of THOSE do you have lying around?). That's all so far. -- -- I wish people would stop running in to my car! Jeff Woolsey National Semiconductor woolsey@nsc.UUCP woolsey@umn-cs.EDU