Help Changing Roger Beep, Beep change - schematic supplied
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Help Changing Roger Beep, Beep change - schematic supplied| Damo666 |
Posted: December 19, 2009 05:54 am
 
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Member  Group: Trusted Members Posts: 139 Member No.: 21,086 Joined: December 04, 2008  |
Hello again guys. I was going to post this in the rf forum as it's cb related, but my question is related to changing a roger beep which is audio related. I have an old Amstrad 901 cb and have established that the beep can be increased or decreased in length by changing C116(near Q21). I'm after creating a wierd and wonderful beep like a peewit sound or anything different to the standard beeep, but haven't a clue what to do. I know it's possible as i heard several of these cb's modded in the 80's and 90's. Here is the schematic - http://www.cbtricks.com/radios/amstrad/cb901/index.htm . Can anybody give any suggestions please? Again, many thanks for any input. Damian.
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| sherlock ohms |
Posted: December 19, 2009 09:20 am
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 Forum Addict ++ Group: Spamminator Taskforce Posts: 1,811 Member No.: 26,125 Joined: September 10, 2009 |
dammit.. i was sure this thread was gonna be smut/porn-related..
 -------------------- "Quotation marks make sentences appear more meaningful."
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| Nothing40 |
Posted: December 19, 2009 10:11 am
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 Forum Addict ++ Group: Spamminator Taskforce Posts: 2,485 Member No.: 181 Joined: October 05, 2002 |
Why's that? -------------------- "we need an e-kick-in-the-nuts button" -Colt45
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| sherlock ohms |
Posted: December 19, 2009 10:27 am
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Forum Addict ++ Group: Spamminator Taskforce Posts: 1,811 Member No.: 26,125 Joined: September 10, 2009 |
wee bit inebriated, misread/misinterpreted the post title..  ..'nuff said  -------------------- "Quotation marks make sentences appear more meaningful."
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| CWB |
Posted: December 19, 2009 02:23 pm
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 Forum Addict ++ Group: Spamminator Taskforce Posts: 13,521 Member No.: 15,154 Joined: May 15, 2008 |
*something* to do with rogering ...
(yer a sick man charlie brown ...) |
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| tekwiz |
Posted: December 19, 2009 11:05 pm
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 Forum Addict ++  Group: Moderators Posts: 23,275 Member No.: 5,746 Joined: July 24, 2006 |
Q20 appears to be the RB oscillator. Altering the value of the caps to the left of it will likely allow you to change the pitch of the beep. Increase to lower pitch, decrease to raise it.
Any other sound would be better obtained by disabling the onboard RB & using a seperate circuit in the mike.  -------------------- Trouble rather the tiger in his lair, than the sage among his books.
For to you, kings & armies are things mighty & enduring. To him, mere toys of the moment, to be overturned at the flick of a finger. Fortuna favet fortibus. |
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| Damo666 |
Posted: December 21, 2009 12:57 am
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Member Group: Trusted Members Posts: 139 Member No.: 21,086 Joined: December 04, 2008 |
Thanks for that Tek. I'll alter the cap's around q20 when i get some time to do it. Are you certain this(Q20) is the oscillator circuitry? Not questioning your expertise or anything, i just want to make sure i don't blow anything while messing in this area. Would it be the 4700pf ceramic cap's that altered the tone?Thanks again buddy. |
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| tekwiz |
Posted: December 23, 2009 01:15 am
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Forum Addict ++ Group: Moderators Posts: 23,275 Member No.: 5,746 Joined: July 24, 2006 |
I'm not 100% certain, but it sure looks that way. The transistor appears to be set up as a twin T oscillator, & your information about altering the cap to Q21(?) tells me that it's likely for the roger beep. Altering the cap value can do no harm in any case, & the 4700pf cap would be the place to start. -------------------- Trouble rather the tiger in his lair, than the sage among his books.
For to you, kings & armies are things mighty & enduring. To him, mere toys of the moment, to be overturned at the flick of a finger. Fortuna favet fortibus. |
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| GPG |
Posted: December 23, 2009 03:07 am
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 Forum Addict ++ Group: Spamminator Taskforce Posts: 5,212 Member No.: 792 Joined: April 25, 2004 |
It's a phase shift oscillator, the caps and resistors between the collector and base provide the shift.
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| Damo666 |
Posted: December 24, 2009 07:38 pm
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Member Group: Trusted Members Posts: 139 Member No.: 21,086 Joined: December 04, 2008 |
Thankyou very much tekwiz and gpg. I will get some alternative cap's and have a mess about.
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| tekwiz |
Posted: December 24, 2009 09:35 pm
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Forum Addict ++ Group: Moderators Posts: 23,275 Member No.: 5,746 Joined: July 24, 2006 |
Thanks for the correction. I had the wrong term.  -------------------- Trouble rather the tiger in his lair, than the sage among his books.
For to you, kings & armies are things mighty & enduring. To him, mere toys of the moment, to be overturned at the flick of a finger. Fortuna favet fortibus. |
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