Hi 2 Q's
I have been given a Carlsbro Cobra 90 Keyboard 3 channel combo with reverb
the reverb was not working. However if you bumped cabinet hard you got the reverb crash from the springs banging and so crudely this proved to me the output was working. Took cab apart and found it only had the output phono (from rev) lead connected, the input signal was detached from the board but rca phono still connected reverb input
I can't see on schematic obtained these connection points, what i can say is the screen and signal for the output from the reverb are connected to marked 2 for screen and 3 for screen. Points marked 1 and 8 are for the disconnected cable
can u say which is which. Rev Accutronics 4BB3A1B
2nd q if i may i took continuity meter setting and just idly checked points then the reverb itself. on the input end i got continuity beep but instead of 0 i was reading 22 to 24, but other 'end' which was t? on input damagedhe output from rev and read 189 to 191 no beep is this right?
I have been given a Carlsbro Cobra 90 Keyboard 3 channel combo with reverb
the reverb was not working. However if you bumped cabinet hard you got the reverb crash from the springs banging and so crudely this proved to me the output was working. Took cab apart and found it only had the output phono (from rev) lead connected, the input signal was detached from the board but rca phono still connected reverb input
I can't see on schematic obtained these connection points, what i can say is the screen and signal for the output from the reverb are connected to marked 2 for screen and 3 for screen. Points marked 1 and 8 are for the disconnected cable
can u say which is which. Rev Accutronics 4BB3A1B
2nd q if i may i took continuity meter setting and just idly checked points then the reverb itself. on the input end i got continuity beep but instead of 0 i was reading 22 to 24, but other 'end' which was t? on input damagedhe output from rev and read 189 to 191 no beep is this right?
Attachments
Thanks very much for reply and info - my apologies for not responding quicker but I've not had best day today, but if I can I shall try assembling again tomorrow
I'm sorry my original message seems to become jumbled when I edited but in essence I do have continuity beep on reverb input. the meter doesn't actually read 0 but in the 20's but does beep. This is the one that's come off the pcb so I don't know which pin 1 or 8 the screen or signal goes to - looking at the drawing its signal to 1 and screen to 8
I shall do tomorrow and report back, thank you
I'm sorry my original message seems to become jumbled when I edited but in essence I do have continuity beep on reverb input. the meter doesn't actually read 0 but in the 20's but does beep. This is the one that's come off the pcb so I don't know which pin 1 or 8 the screen or signal goes to - looking at the drawing its signal to 1 and screen to 8
I shall do tomorrow and report back, thank you
somethings wrong
Od dear I've got a bigger problem - it worked when first had it but reverb didnt. Since re connected the lead back onto the pcb with pin 1 signal and 8 screen on meter checked and yes gets continuity beep but instead of 0 gets a low 22 reading. meter and visual phono ends reconnected unit onto its springs - damn awkward - and got to turn o point
Turned off again ever so quick as a loud noise frm the cabinet - obviously something gone wrong or i have made mistake
I didn't dare leave on in case burnt out something else
Guess i will need to take all apart again and connect up with reverb leads disconnected and if all ok re -investigate the reverb
Any ideas?
Od dear I've got a bigger problem - it worked when first had it but reverb didnt. Since re connected the lead back onto the pcb with pin 1 signal and 8 screen on meter checked and yes gets continuity beep but instead of 0 gets a low 22 reading. meter and visual phono ends reconnected unit onto its springs - damn awkward - and got to turn o point
Turned off again ever so quick as a loud noise frm the cabinet - obviously something gone wrong or i have made mistake
I didn't dare leave on in case burnt out something else
Guess i will need to take all apart again and connect up with reverb leads disconnected and if all ok re -investigate the reverb
Any ideas?
Hi
Took it apart all parts looked fine so leaving the reverb disconnected I nervously re connected....and works as it did when first received so not damaged anything thank goodness - fault must be with the reverb itself or, on the pcb itself - possibly explaining the lead being off intentionally, not old age??
i see 2 3 and 4 spring reverbs being sold on ebay for circa £15 to £20 but if i buy one only to find same fault this means risking damage when i turn on and of course the cost. So I think I will have to sell as it is reflecting cost of a replacement reverb - does it matter if 2 3 or 4 springs by the way? thank you
Took it apart all parts looked fine so leaving the reverb disconnected I nervously re connected....and works as it did when first received so not damaged anything thank goodness - fault must be with the reverb itself or, on the pcb itself - possibly explaining the lead being off intentionally, not old age??
i see 2 3 and 4 spring reverbs being sold on ebay for circa £15 to £20 but if i buy one only to find same fault this means risking damage when i turn on and of course the cost. So I think I will have to sell as it is reflecting cost of a replacement reverb - does it matter if 2 3 or 4 springs by the way? thank you
Make sure you had the ground right. Measure from the soldered shield (which we know is ground),
to either of the two open pads. The pad with a short to the shield is the grounded pad.
to either of the two open pads. The pad with a short to the shield is the grounded pad.
Thanks so much for the reply however i'm not sure whats meant - pad? sorry if being daft it's getting late; the connectors into and out of the reverb unit are rca phono, these connect to the mixer pre amp on pins 1 and 8 - this was disconnected lead, and pins numbered 2 and 3 circuit info attached managed get page 1 only so inside size limit
surelt not relevant but mention in case I replaced the rca phono sockets on the accutronics, which were very surface corroded used a new pair brass from Farnels - the wires from the ends of the accutronics are green and black green going to _+ve ie tip of phono black to screen; as I have said previously the one end on continuity setting f the meter reads across tip and screen as a short - continuity beep from meter but istead of a '0' reading shows around 22 other end no continuity reads around 220 - does vary according how steady these old hands can hold the probes!
Hi there
I have this circuit diagram as one saved on pdf to A3 size and also a pg 1 and pg 2
Interestingly all the same circuit it is of the keyboard cobra 90 over 3 channels but shows channel 1 with one input where it has 2 as have the 2nd and 3rd channel inputs I'm sure you've read that the wires were off this pcb, and my original enquiry was which way round ie signal and screen (ground) to reconnect to the 2 points marked 1 and 8 I didn't have schematic at that time. Signal and screen other end connected to pins 2 and 3 2 screen 3 signal
Normally when you use meter to check continuity the display goes to 0 and emits a tone.
I got this tone, but I have never seen a number in the screen before so albeit a low 20 to 22 and its making continuity noise I mentioned it in case any relevance - the other 'end measure around 200 and def no continuity beep
I don't know what the items are each end of the spring - small coils is it to create electro magnetic?/ Anyway 2 very fine wires black and green go into these green to rca phono tip or signal and black to phono sleeve or ground
I have this circuit diagram as one saved on pdf to A3 size and also a pg 1 and pg 2
Interestingly all the same circuit it is of the keyboard cobra 90 over 3 channels but shows channel 1 with one input where it has 2 as have the 2nd and 3rd channel inputs I'm sure you've read that the wires were off this pcb, and my original enquiry was which way round ie signal and screen (ground) to reconnect to the 2 points marked 1 and 8 I didn't have schematic at that time. Signal and screen other end connected to pins 2 and 3 2 screen 3 signal
Normally when you use meter to check continuity the display goes to 0 and emits a tone.
I got this tone, but I have never seen a number in the screen before so albeit a low 20 to 22 and its making continuity noise I mentioned it in case any relevance - the other 'end measure around 200 and def no continuity beep
I don't know what the items are each end of the spring - small coils is it to create electro magnetic?/ Anyway 2 very fine wires black and green go into these green to rca phono tip or signal and black to phono sleeve or ground
