Redifon Bt500/BT1002 transmitters (Manuals)

[SamTheDog]

Hi All.
I'm looking for service / user manuals for the REDIFON / Rediffusion BT500/BT1002 series
of MF Broadcast transmitters, and the HCD precision frequency source that these use.

I have a 500w version here that was stored in a damp storage unit for a few years. I've got one of the
power supplies running. It needed many parts replacing, Mostly Op-Amps and opto-isolators, ttl-logic.

Other modules have had the obvious parts replaced too, The dual oscillator frequency source seems to
be faulty. and possibly other units are faulty too.

So please.
If you or anyone in your contacts-book has manuals or spares for these, please get in touch!

Cheers S-T-D

[jvok]

Might be worth joining mb21's tx-list and asking there. I know there's a few old broadcast types on there that might have something.

Tell them you're converting it for 160m.

[SamTheDog]

Hi jvok. Cheers Mate!
I had a look at MB21 but there's nothing obvious... But you're right, there's nothing like joining and asking.... Maybe get them to suggest a DDS-unit to save me having crystals made too...!


All the best
S-T-D

[SamTheDog]

Redifon BT500 update....
---------------------------------
Now have the dual High-Stability HCD oscillator and changeover unit working. Needed a few components changing and now both oscillators working very well
I set them up on the original IBA-Wyvern channel of 954 and they settle in nicelyafter an hour of warming up time and are pretty stable (+/- well under 1Hz) .

This morning had both power-supplies running but both still have some minor faults.
One has an intermittant -5v rail and the other isn't indicating that it's +15 is OK.. Both of these were damp so needed drying out and rusty parts replacing (Mostly transistors, 74-series logic, and opto-isolators.

[SamTheDog]

Redifon BT500 update....
---------------------------------
Now have the transmitter producing around 260 watts. on 954kHz. PA output levels are all over the place, so they will need
setting-up, and only half of the modulation amplifiers are currently working. But it actually produces 260 watts of reasonable AM.

Still some work to do on the PA units ,
A few repairs needed on the monitor/indication-section of one of the power supplies,
Loads of sticky / intermittant push-buttons to clean or replace.
audio/Mod-Amp faults to solve.

[projuicer]

Latterly Sunshine Radio Hereford?

Reach out to Sunshine and ask if they've still got any paperwork? By virtue of starting out at a pirate themselves they might be sympathetic!

[SamTheDog]

Hi Projuicer.
It's in my 1981 book as R.Wyvern with 200w, and in the 2002 book as classic gold 954 with160watts. Not listed in the 2009 wrth, so probably off the band by then... did they then become sunshine?

Cheers
S-T-D

[projuicer]

Started as Wyvern
Murfin Media bought the AM - Classic Hits
Laser Broadcasting bought that, rebranded to Sunshine
Laser didnt pay the land owner, which resulted in 954 getting switched off
Laser went bust, everything got messy, the Worcester/Hereford Licence got cancelled
Murfin Media now have Sunshine on 855khz (Villa Farm), 105.9 (Wooferton), 106.2 (Ridge Hill), 107 (Monmouth) and 107.8 (Abergavenny and Clee Hill)

That 954 TX would have been Sunshine when finally switched off, yes.

[SamTheDog]

Holy Cow.. That's a lot of changes... Nice Timeline projuicer.....

[SamTheDog]

I've sent an e-mail to the station just-in-case they have any manuals in the archives....

[SamTheDog]

All the modulation amplifiers are now working, and both power-supplies are indicating thier status correctly. Just need to set-up the RF amplifiers and give it a general tune / service now it's been repaired..

Still no manuals at the moment though.