BOB KROVETZ <krovetz@research.nj.nec.com>
I saved the following posting
from rec.video. I am submitting it for information only (if you screw up
your Betamax following the instructions it is not my fault!):
Article 8095 of rec.video:
For you fellow Sony SL-HF900
fans out there in netland who missed the mod, here is my most up-to-date
proven procedure. So far I have modified two units sucessfully and another
person has modified his unit sucessfully using this procedure.
CONVERSION OF SL-HF900 FOR BETA-Is
OPERATION
This modification enables an
SL-HF900 to have the same record/playback capabilities as the SL-HF750:
o Record only in BIs (not in
regular BI) o Playback BIs (when SuperBeta switch is on) o Playback BI
(when SuperBeta switch is off) o BIs is recorded regardless of the position
of the SuperBeta switch.
There are 4 steps to the modification:
1. Enabling the recording mode
switch for 3 position operation.
2. Enabling the A' and B' heads
to be selected in BIs recording.
3. Enabling the BII/BIII deemphasis
to be selected instead of BI(normal) deemphasis when playing back in BIs.
4. Enabling the BI gain for the
chroma recording level.
PARTS REQUIRED
____________________________________________________________________________
___
Qty Sony PN Description Unit
Price Total Price
____________________________________________________________________________
___
3 8-729-900-89 Transistor DTC144ES
$ 1.00 $ 3.00 1 8-719-911-19 Diode 1SS119 $ 0.65 $ 0.65 1 1-515-529-11
Relay $ 11.75 $ 11.75 1 1-247-831-00 Resistor 1K $ 0.20 $ 0.20 (any old
1/8W 1K resistor will do) Shipping and handling from Sony: $ 1.50 Total
Cost: $ 17.00
____________________________________________________________________________
___
ENABLING THE RECORDING SWITCH
FOR 3 WAY OPERATION:
1. Remove the top cover (4 screws).
Remove bottom cover (approx 10 screws). Remove front panel (4 screws and
four snap retainers).
2. On the front panel, locate
the hole for the record mode switch and notice that the panel hole is larger
than the trim cover hole. Using an X-acto knife, cut the trim cover to
the same size as the panel hole for the record mode switch so the switch
can slide to the left.
3. On the FR-14 Cassette Switch
Control board, locate S019 (record mode switch) and remove the white plastic
piece that prevents the switch from sliding to the left.
4. Locate the FP-4 Power Switch
Board just to the left of the cassette door. Gently pull the lower locking
tab away from the board and lift the board out of its mount.
5. Locate the FF-3 TV/VTR Switch
Board just to the right of the cassette door. Gently pull the lower locking
tab away from the board and lift the board out of its mount.
6. Unsnap the Peak Level Meter
module from its mounting location, unplug its cable from the FR-14 board,
and remove the meter module.
7. Loosen the FR-14 board by
removing the 3 screws holding it. >>NOTE<< THAT THE CENTER SCREW
IS LONGER THAN THE TWO SIDE SCREWS. Because all cabling to the board is
soldered, not socketed, the board cannot be removed. Lift and rotate the
top of the board away from the unit to gain access to the solder side of
the board.
8. At S019 (record mode switch),
solder an insulated wire on the solder side of the board from the leftmost
terminal of the switch to the junction of R19 and R20.
9. Reinstall the FR-14 board,
makeing sure the long screw is used in the center and the short screws
on the sides)
10. Reinstall the FF-3 board,
the FP-4 board, and the Peak Level Meter module (don't forget to plug it
back in).
11. Reinstall the front panel.
When installing the front panel, take care that the audio level sliders
and record button properly engage the controls and switch on the FR-14
board. Ensure that the two retainers on each side are properly snapped
into place.
12. Power up the VCR and verify,
by sliding the record mode switch thru all three positions, that the indicator
on the front display switches thru BI, BII, & BIII.
ENABLING THE A' AND B' HEADS
TO BE SELECTED WHEN RECORDING IN BIs:
1. Set the unit up on it's right
side (cassette mech end up) with the bottom toward you, remove the four
screws holding the SS-53 System Servo Board, and rotate the board down
out of the way.
2. Unplug the cable harness feeding
the bottom of the RP-24 board (board inside metal shield behind cassette
mechanism).
3. Move the SS-53 board back
into position and tack it in place with one screw (do not fully reinstall
yet) and set the unit back down.
4. Remove the two screws holding
the RP-24 box and gently pull the RP-24 board up far enough until you can
unsnap and remove the front cover of the box.
5. Unplug the two cables connected
to the RP-24 board and remove the RP-24 board box from the VCR.
6. Remove the rear cover of the
RP-24 board box to gain access to the solder side.
7. Locate RY1 on the board, unsolder
and remove the 2 jumpers in the square, and install the relay (1-515-529-11).
Due to pin spacing, the relay can only be installed one way.
8. Locate D001 and install the
diode (8-719-911-19). Match the band on the diode to the band on the silkscreen
legend on the board.
9. Locate Q012 and install a
transistor (8-729-900-89). Match the outline of transistor case to outline
of silkscreen legend on the board.
10. Locate JW24 (jumper missing)
and install a jumper wire.
11. Locate R085 (missing) and
install a jumper wire (not a resistor).
12. Reinstall the rear cover
on the RP-24 board box, hold the box in place in machine, connect the two
cables unplugged in step 5, reinstall the front cover, move the RP-24 box
into place, and secure it with two screws.
13. Set the unit up on it's right
side (cassette mech end up) with the bottom toward you, remove the screw
holding the SS-53 System Servo Board and rotate the board down out of the
way.
14. Reconnect the cable to the
bottom of the RP-24 board.
15. Move the SS-53 board back
into position and secure it with four screws.
16. Observe the VI-10 board and
locate CN203 and CN204. Ensure that the jumper located between the two
connectors is installed. If there is no jumper there:
a. Set the unit up on it's left
side (cassette mech end down) with the bottom toward you.
b. Remove the four screws holding
the VI-10 System Servo Board and rotate the board down.
c. Install the missing jumper
between CN203 and CN204.
d. Move the VI-10 board back
into position and tack it in place with one screw (do not fully reinstall
yet).
17. Set the unit back down.
18. Power up the VCR and verify
that when sliding the record mode switch to the BI position, a clicking
sound is heard (the new relay on RP24 board picks to select A'B' heads).
A very faint click may be heard when switching out of BI as the relay deenergizes.
ENABLING BII/BIII DEEMPHASIS
FOR BIs PLAYBACK:
1. Set the unit up on it's left
side (cassette mech end down) with the bottom toward you.
2. Remove the four screws holding
the VI-10 System Servo Board and rotate the board down.
3. Locate Q723 and remove the
jumper (looks like a resistor) between the emitter and collector.
4. Install transistor (8-729-900-89).
Match the outline of the transistor case to outline of the silkscreen legend
on the board.
5. Locate JW168 (jumper missing)
and install jumper wire.
6. Locate JW88 (jumper missing)
and install jumper wire.
7. Do not reassemble. Proceed
to the next section.
ENABLING BI GAIN FOR CHROMA RECORDING
LEVEL
1. Locate Q659 and install a
transistor (8-729-900-89). Match the outline of the transistor case to
the outline of silkscreen legend on the board.
2. Locate R677 and install the
1K resistor (1-247-831-00).
3. Move the VI-10 board back
into position and secure it with four screws.
4. Reinstall the bottom panel
and secure it. Set the unit back down and reinstall the top cover.
CHECKOUT:
Record material in BIs and verify
picture quality (if your VCR was adjusted properly before this modification,
there shouldn't be any adjustment needed for recording/playback in BIs.)
REMINDERS:
Don't forget to leave the SuperBeta
switch on when playing back BIs tapes otherwise the picture will be distorted.
As special effects (slow motion
and freeze) are optimized for BII and BIII, there may be noise bars in
BI special effects.