Back to the SSB board
Locked
 
|
Hi all,
Well I have finally started looking for the fault on my SSB board after about 9 months! For some reason I have no receive when the board is plugged in. If I short out pins 1 and 3 of J9 and J10 I get receive no problem, so it would appear to be a fault on the SSB board. I have checked the crystals to ground, all seems OK. I have checked the voltages on the pin diodes and again, all would seem well. In fact, other than a few small stray voltages, the only major anomaly I can find is a voltage on U4-3 of 6V on receive. The manual states 0.6 volts. I would love any thoughts to point me in the right direction please? 73 Ian -- Ian J Maude G0VGS SysOp GB7MBC DX Cluster Member of RSGB, ARRL, GQRP K2 #4044 _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
Ian,
Have you tried checking the small toroid RF Chokes for shorts to the crystal can? That is a common cause of the problem you describe. Just stick a small piece of paper between the chokes and the crystal cans for a quick check - if the receiver comes to life, rewind the chokes (being careful not to scrape the wire insulation). You can ignore the voltage at U4-3 until after you have properly adjusted the carrier balance - that voltage depends on the exact setting of the balance pot. 73, Don W3FPR > -----Original Message----- > > Hi all, > Well I have finally started looking for the fault on my SSB board after > about 9 months! For some reason I have no receive when the board is > plugged in. If I short out pins 1 and 3 of J9 and J10 I get receive no > problem, so it would appear to be a fault on the SSB board. > I have checked the crystals to ground, all seems OK. I have checked the > voltages on the pin diodes and again, all would seem well. In fact, > other than a few small stray voltages, the only major anomaly I can find > is a voltage on U4-3 of 6V on receive. The manual states 0.6 volts. > I would love any thoughts to point me in the right direction please? > > 73 Ian > No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.432 / Virus Database: 268.17.0/639 - Release Date: 1/18/2007 6:47 PM _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
Don Wilhelm wrote:
> Ian, > > Have you tried checking the small toroid RF Chokes for shorts to the crystal > can? That is a common cause of the problem you describe. Just stick a > small piece of paper between the chokes and the crystal cans for a quick > check - if the receiver comes to life, rewind the chokes (being careful not > to scrape the wire insulation). > Thanks for the info Don. Unfortunately it is not the cause in this case. I have checked the continuity of all the toroids and all seems well there. I also had a response from Stewart G3RXQ and I have looked at what he mentioned. I don't think it is the VOXDET Stewart as I actually have *some* receive with the board plugged in, just well down on where it should be although I have looked very carefully for shorts but cannot find any currently. A S9 sig on the meter without the board does not move the meter with it plugged in and the receive is well down to match. Any other ideas gratefully received. Skype ID is ian-g0vgs Ian -- Ian J Maude G0VGS SysOp GB7MBC DX Cluster Member of RSGB, ARRL, GQRP K2 #4044 _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
In reply to this post by Don Wilhelm-3
I guess I should mention that this board has worked perfectly well
before it went deaf. I had tried some of Stewarts SSB mods and back engineered them before it failed. I have checked and double checked all the parts of the circuit I messed with though and all seems fine in that area. Ian Don Wilhelm wrote: > Ian, > > Have you tried checking the small toroid RF Chokes for shorts to the crystal > can? That is a common cause of the problem you describe. Just stick a > small piece of paper between the chokes and the crystal cans for a quick > check - if the receiver comes to life, rewind the chokes (being careful not > to scrape the wire insulation). > Thanks for the info Don. Unfortunately it is not the cause in this case. I have checked the continuity of all the toroids and all seems well there. I also had a response from Stewart G3RXQ and I have looked at what he mentioned. I don't think it is the VOXDET Stewart as I actually have *some* receive with the board plugged in, just well down on where it should be although I have looked very carefully for shorts but cannot find any currently. A S9 sig on the meter without the board does not move the meter with it plugged in and the receive is well down to match. Any other ideas gratefully received. Skype ID is ian-g0vgs Ian -- Ian J Maude G0VGS SysOp GB7MBC DX Cluster Member of RSGB, ARRL, GQRP K2 #4044 _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
In reply to this post by Ian Maude
Hi Ian,
When I first plugged in my ssb option, I lost all receive too (extremely weak). I checked all the things mentioned in the manual, and then I checked the things mentioned on the reflector, all to no avail. Next I decided to to check for unwanted paths to ground, referring to the schematic. Between the P2 header connector pin 1 and c1, I found (with dmm) an unwanted path to ground. Everything looked fine, but when I pried up the black plastic on the header, between pins 1 and 2, I found a microscopic sized hair of solder, taking pin 1 to ground. It's not always visable, but as Don says, check the soldering (hi). Good luck with the troubleshooting, Paul -ve1dy- On 1/21/07, Ian J Maude <[hidden email]> wrote: > Don Wilhelm wrote: > > Ian, > > > > Have you tried checking the small toroid RF Chokes for shorts to the crystal > > can? That is a common cause of the problem you describe. Just stick a > > small piece of paper between the chokes and the crystal cans for a quick > > check - if the receiver comes to life, rewind the chokes (being careful not > > to scrape the wire insulation). > > > Thanks for the info Don. Unfortunately it is not the cause in this > case. I have checked the continuity of all the toroids and all seems > well there. I also had a response from Stewart G3RXQ and I have looked > at what he mentioned. > I don't think it is the VOXDET Stewart as I actually have *some* receive > with the board plugged in, just well down on where it should be although > I have looked very carefully for shorts but cannot find any currently. > A S9 sig on the meter without the board does not move the meter with it > plugged in and the receive is well down to match. Any other ideas > gratefully received. > > Skype ID is ian-g0vgs > > Ian > > -- > Ian J Maude G0VGS > SysOp GB7MBC DX Cluster > Member of RSGB, ARRL, GQRP > K2 #4044 > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > -- Paul - ve1dy - Halifax, NS QRP-L #416, SKCC #91 www3.ns.sympatico.ca/ppike _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
In reply to this post by Ian Maude
Ian,
What mods did you try, and then remove ? Did the board work OK after you removed the mods ? None of my mods involve work around the Xtal filter or diode areas, but they are round U3 and close to U2 and U4. Is it possible that you may have put on a short ? Stewart G3RXQ On Sun, 21 Jan 2007 15:02:41 +0000, Ian J Maude wrote: > I guess I should mention that this board has worked perfectly well > > before it went deaf. I had tried some of Stewarts SSB mods and back > engineered them before it failed. I have checked and double checked all > the parts of the circuit I messed with though and all seems fine in that > area. > > Ian > > Don Wilhelm wrote: >> Ian, >> >> Have you tried checking the small toroid RF Chokes for shorts to the crystal >> can? That is a common cause of the problem you describe. Just stick a >> small piece of paper between the chokes and the crystal cans for a quick >> check - if the receiver comes to life, rewind the chokes (being careful not >> to scrape the wire insulation). >> > Thanks for the info Don. Unfortunately it is not the cause in this > case. I have checked the continuity of all the toroids and all seems > well there. I also had a response from Stewart G3RXQ and I have looked > at what he mentioned. > I don't think it is the VOXDET Stewart as I actually have *some* receive > with the board plugged in, just well down on where it should be although > I have looked very carefully for shorts but cannot find any currently. > A S9 sig on the meter without the board does not move the meter with it > plugged in and the receive is well down to match. Any other ideas > gratefully received. > > Skype ID is ian-g0vgs > > Ian _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
|
|
In reply to this post by Ian Maude
Ian,
Look at the KSB2 schematic and locate the components at the top of the page (filter and its switching). First try CW mode with the filter on the RF Board selected (not OP1). Then be certain that everything marked 'RXC' is at 5 to 6 volts (the source is firmware chip U1 pin 22), and that those points marked 'RXS' are near zero volts (source is U1 pin 21). If those two voltages are correct that should place the proper diodes in either a conducting state or a cutoff state which will route the signal just like the jumpers in J9 and J10 do (D6 and D10 conducting - also D9 and D13). When the RXS and RXC signal states are reversed, the signal path is through the filter on the SSB board - selecting the OP1 filter should activate RXS and cause RXC to go near zero volts. T1 and T2 are in the signal path when the OP1 filter is selected, so if you have trouble only with that filter, look at T1 and T2, but if you have trouble when the variable filter is selected, look for the problem in the control voltages or in the switching diodes (and the associated resistors and chokes). All diodes should have their cathode ends pointed up away from the board. 73, Don W3FPR > -----Original Message----- > > > Thanks for the info Don. Unfortunately it is not the cause in this > case. I have checked the continuity of all the toroids and all seems > well there. I also had a response from Stewart G3RXQ and I have looked > at what he mentioned. > I don't think it is the VOXDET Stewart as I actually have *some* receive > with the board plugged in, just well down on where it should be although > I have looked very carefully for shorts but cannot find any currently. > A S9 sig on the meter without the board does not move the meter with it > plugged in and the receive is well down to match. Any other ideas > gratefully received. > > Skype ID is ian-g0vgs > > Ian > > -- > Ian J Maude G0VGS > SysOp GB7MBC DX Cluster > Member of RSGB, ARRL, GQRP > K2 #4044 > > _______________________________________________ > Elecraft mailing list > Post to: [hidden email] > You must be a subscriber to post to the list. > Subscriber Info (Addr. Change, sub, unsub etc.): > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/subscribers.htm > Elecraft web page: http://www.elecraft.com > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.432 / Virus Database: 268.17.0/639 - Release Date: > 1/18/2007 6:47 PM > No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.432 / Virus Database: 268.17.3/642 - Release Date: 1/20/2007 10:31 PM _______________________________________________ Elecraft mailing list Post to: [hidden email] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com |
«
Return to Elecraft
|
1 view|%1 views
| Free forum by Nabble | Edit this page |