Bryston bp 25 service manual

Page 1

EQUEUGJDD ENGINEERING MEMO i970207

RE: CONFLICTS BETWEEN BRYSTON'S BP25 & B60R friga- 171II=EEzJogg7
REMOTE CONTROLS & OTHER EQUIPMENT -
including "Meridian" CD Players ENGR: W3

In some installations it has been observed that the Bryston IRTX remote control, supplied with both BP25 preamps and B60R integrated power
amps. has inadvertently initated certain control functions in other pieces of equipment also equiped with infra red remote controls. "Meridian"
CD players, in particular. have experienced this problem. The cause of this problem. of course, is that the other equipment just so happens to
be using codes similar enough to the codes used by the Bryston IRTX remote control to misinterpret its transmissions. There is, however, a
fairly simple way to remedy this problem: changing the data stream being transmitted by the lRTX remote. This can be done by programming a
different ADDRESS segment on the IRTX's transmitter IC (integrated circuit), The ADDRESS of the transmitted data is altered by changing the
connections of the first four pins (pins 1 to 4) of the MC145026 which are normally tied to ground. Any or all of these pins can be disconnected
from ground (and thus left floating) withoug degrading performance
in any way. Of course, if the if the ADDRESS of the transmitted dta
is changed, thend the reveiver lC (MC145027) located in the BP25 or
BBOR must also be changed to match it. The ADDRESS
programming pins on both the transmitter and receiver lC's are

I Address switch In t? RIM-25 e RIM-6|) hand held remote: I
, ,\ ,

L

I-IDIH

'5
MCI 45026 JCl

. I (
identical, so what ever changes are made to the connections of I; C\J/:IE:
pins 1 to 4 of one chip must be made to the other. Newer BP25 m 04 m WEI mo EN
and BGDR units are being equipped with four element DIP switches 33 R2 UCKW grad ' I my:
to make such ADDRESS changes easier, and a new version of the \\ C3 i-WISI [ISQGI ZZCF IOK mar
IRTX hand held remote control (renamed "RCZB" for the BP25, and I R4 .fi/mmémxr VP £2K2267K}fl
"RC60" for the B60R) will have a similar DIP switch, In older units, SD 5; {IOKO} m0R9\I/FB 7 -tcr<0\»
traces must be cut. however. to reprogram the ADDRESS data. On 2 E] ct Eggdzm C302 Liming] t%l
the IRTX transmitter, pin #1 is connected to ground with a split a Hwy; -,» Eav- MCMOII (WWI LIIDI %
pad which is normally bridged with solder. This solder bridge can 3 Q VIOKm I114 w) Emma/fill);
be removed to affect an address change. it Q C) (j $0} Gl/I L A

_ / 00

Transmitter circuit board In the IRTX hand held remote

______________________________ _I
5st remote control reoelver seotlon (verslon 1.6) This 59' Pad I5 normally 055d VIII" 50- IIWI I
I. ________________________ .I easily be opened by remwipg the solder bridge. I
I DIP switch for I O s on or no PM It melons I I
I setting h'ansmittl I W can. I «Moog :
I , receive address I I
I (all .vwrrches normally 0N) I a I

I I D
- - O a m :
I zoo - 0 (w quzTELIgW) T I
I 3. cc 2N? o a m: I
: VDDN 749w - - - O '-I' OTIIJKIO 0J0 I
I @ fiI 7 ' I This trace on the bottom side of the board was brought out in I
I q toK )9 7 IVICI4302/ a loop to make it easier to cut. fl. Whatever traces on this I
I w 3333! 3 Bl . board between pins 1 to 4 of the MC145026 and ground are '
I g: 45027 o@ opened, the matching connections between similarly numbered I
I INSBI I pins on the MC145027 in the receiver section must also be I
L ________________________ _I Lapened .I

Transmitter olroult heard In the RCZSIHGGII hand held remote
559 I BP25 remote control reoelver r ______________________________ 1
remote eontro receiver I C . .g - RCZSB/I 2 i I
eeotion(version1.5) seetlon(verslon1.5) I IDEPEELJDU 29 OCT 97 V :
0n the B60 r70; This Tie-mini? (TI-Iii- ' "an-ti" I I
amplifier main I 3' 'i RC 7 I ~ prior to the inclusion of ' I
board the IR I a % E I the DIP switch ~ there are I
receiver address I a 3 t: I short tracks between the 1st I
can be altered by ' 9 E E I four pins of the MC145027 I
cutting out a I .3 I integrated circuit and the I
jumper as shown I t I ground trace. Cut any or all I
to right. Set the I '6 . @ I of these short tracks being I
transmitter Iv! . I careful not to cut the main I
address DIP switch .3» e - I ground track. In maIch the I
to match this I3 § I connections found on the I I
new address, iei IE; I transmitter between pins 1 to I I (,\ I
1-0- 2-011. ' . ' 4 of the MC145026 and ' I . \J V V \J V I
3-oni 4-on. I I ground. .- _ _ _ _ a I I 1Sggsthlis DIP sw1tch to {natch (Ihe same-SIP swlgtlgh fo'ltmhd 1nt the I
I I I I n preamps or in egrage amps WI 011 Sin c es 0

I I wag-I 3 I I allow setting the remote control recierer address, traces on the I
I I MCI43027 g PCB connecting the first 4 pins of the MC145027 integraged I
I I ICU! HUB. . I I circuit to a ground track must be cut to match the DIP switch I
L _____ 4-592] _______ J Lelements that are open. _______________ J

Updltld In It rm 2mm