TR720 airband transceiver mic connection

The TR720 airband transceiver is no-longer serviced. Parts are not available from the manufacturer and service costs equal or exceed the resale value.

TR720 replacement NiCad battery

Unfortunately demand for this replacement pack has dropped to a point whereby its continued manufacture has become uneconomic. NiCads do not last for ever if stored on the shelf awaiting sale, for this reason regular manufacture and rotation of stock is most important.

The battery comprises of 6 cells physically strapped together in a custom plastic battery case, they are soldered in series to provide a total nominal voltage of 9.6V, the capacity of the standard BP45 battery was 450mAhr and the larger BP75 750mAhr (the larger BP75 battery required a different charger). An electrical view of the BP45 standard battery pack is given above. The early plastic cases were sealed, unfortunately this makes replacement of the batteries difficult, the later cases had screws on the top face which assists access immensely. The battery is offered to the radio and 'twisted through 90 degrees' where the contacts mate with the bottom of the radio. The plastic house for the battery and dry battery case are no-longer available (in fact no TR720 accessories are available now, however servicing of the transceiver is possible as spare parts are still available).

For your information, the batteries were available until the end of February 2000 as sales items, price was £75.00 (BP45 standard size) and £90.00 (BP75 heavy duty) including VAT with P&P being additional.

It may be possible to have batteries re-manufactured here in the UK by one of the replacement battery manufacturers:

Please do not forward battery packs or chargers to us, we cannot economically repair them.

If you have a drop-in or rapid charger which has become faulty, the only way to provide a replacement charger for the BP45 is to use a regulated 12V power supply fed through a current limit resistor (value between 10 OHMS and 33 OHMS) via a 3.5mm mono jack plug (centre positive)... you can see the BP45 battery charge socket in the photograph above - we can supply a charger of this type (made to order) priced at £18.50 plus £3.50 P&P in the UK inc VAT.

If you have a BP75 battery without charge socket, we cannot assist, sorry. Early battery packs were sealed and it may not be possible to re-manufacture (repair) them, later battery packs had 'screw access' to the top of the pack.

TR720 microphone connection

A popular request is for the pin-out connection for the TR720 speaker / microphone socket on the top of the TR720. No accessories are available for the TR720 at this time but the pin-out details are available as a small Acrobat PDF file (11kB) - click here.

We do not have a list of suitable speaker-microphones or headsets. In the past, engineers spent many hours adding decoupling capacitors to some speaker-microphones / headsets and ensuring DC was allowed to pass to others in
order to drive the electrect microphone insert. There are no details of our specific ad-hock modifications applied. However, a drawing for one compatible microphone and adapter has been located which was supplied by a company in the USA (Communication Specialists Inc, 426 W. Taft Ave, Orange, CA 92665-4296, USA Tel 00 1 714 998 3021.
A small Acrobat PDF file (13kB) is provided here.

Due to continuous developments, AOR reserves the right to make design and specification changes for product improvement without prior notice. The performance specification figures indicated are nominal values of production units. There may be some deviation from these values in individual units.

TR720 Bulletin Page

TR720 replacement NiCad battery

TR720 microphone connection