Tektronix 2445 Readout is no good , video included
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From: NetSpid3r on 16 Nov 2007 15:14 On Nov 16, 6:57 am, Jim Yanik <jya...(a)abuse.gov> wrote: > "NetSpi...(a)gmail.com" <NetSpi...(a)gmail.com> wrote in news:19dc4e5b-d326- > 4c17-9bc9-bb21fa6f0...(a)a28g2000hsc.googlegroups.com: > > > > > > > Jim Yanik wrote: > >> "NetSpi...(a)gmail.com" <NetSpi...(a)gmail.com> wrote in > >>news:1195075563.961231.101880(a)57g2000hsv.googlegroups.com: > > >> >http://video.yahoo.com/video/play?vid=1466538 > > >> > The readout looks bad , i can see jumpy dots ,instead of clear numbers > >> > as in the other 2445 . > >> > i replaced those 3 47uf caps on the A5 board (control board) , and it > >> > didn't helped . > >> >http://img110.imageshack.us/img110/2372/image015pn5.jpg > > >> 2445 non-B scopes have separate R-O boards. > >> the signal from them feeds into the vertical on the main bottom board. > >> try swapping the readout boards. > >> IIRC,there's also a pot to adjust R-O crawl/jitter. > >> see the cal procedure in your service manual. > > >> On "B" models,the readout is integrated to the A5 uP board. > >> "B" model A5 uP boards are NOT swappable with earlier versions. > > >> -- > >> Jim Yanik > >> jyanik > >> at > >> kua.net > > tried play with jitter , didn't do the trick ... > > > and you are right about A5 in the 2445 , the R-O is not on this > > board , i just did a swap with a good 2445 A5 and got the same jerky > > readout . > > > what component is making the problem in the R-O of the 2445 ? > > caps ? or something else ? > > possibly caps,or a bad hybrid on the main board. > Does it twitch in the vert or horiz direction,or both? signal trace > solid,in both V and H axes? > This may be where you have to scope every decoupled PS supply line. > could even be some of those 0.1uf DIP caps that are all over every board. > > -- > Jim Yanik > jyanik > at > kua.net trace is solid , no trace problems . and one thing i noticed , when i control the read out intensity fully CW , the R-O shifts upwards ...
From: Jim Yanik on 16 Nov 2007 20:08 "NetSpid3r(a)gmail.com" <NetSpid3r(a)gmail.com> wrote in news:28ac4545-7a53-4594-83d8-910b6ccf1d63(a)e4g2000hsg.googlegroups.com: > On Nov 16, 6:57 am, Jim Yanik <jya...(a)abuse.gov> wrote: >> "NetSpi...(a)gmail.com" <NetSpi...(a)gmail.com> wrote in >> news:19dc4e5b-d326- >> 4c17-9bc9-bb21fa6f0...(a)a28g2000hsc.googlegroups.com: >> >> >> >> >> >> > Jim Yanik wrote: >> >> "NetSpi...(a)gmail.com" <NetSpi...(a)gmail.com> wrote in >> >>news:1195075563.961231.101880(a)57g2000hsv.googlegroups.com: >> >> >> >http://video.yahoo.com/video/play?vid=1466538 >> >> >> > The readout looks bad , i can see jumpy dots ,instead of clear >> >> > numbers as in the other 2445 . >> >> > i replaced those 3 47uf caps on the A5 board (control board) , >> >> > and it didn't helped . >> >> >http://img110.imageshack.us/img110/2372/image015pn5.jpg >> >> >> 2445 non-B scopes have separate R-O boards. >> >> the signal from them feeds into the vertical on the main bottom >> >> board. try swapping the readout boards. >> >> IIRC,there's also a pot to adjust R-O crawl/jitter. >> >> see the cal procedure in your service manual. >> >> >> On "B" models,the readout is integrated to the A5 uP board. >> >> "B" model A5 uP boards are NOT swappable with earlier versions. >> >> >> -- >> >> Jim Yanik >> >> jyanik >> >> at >> >> kua.net >> > tried play with jitter , didn't do the trick ... >> >> > and you are right about A5 in the 2445 , the R-O is not on this >> > board , i just did a swap with a good 2445 A5 and got the same >> > jerky readout . >> >> > what component is making the problem in the R-O of the 2445 ? >> > caps ? or something else ? >> >> possibly caps,or a bad hybrid on the main board. >> Does it twitch in the vert or horiz direction,or both? signal trace >> solid,in both V and H axes? >> This may be where you have to scope every decoupled PS supply line. >> could even be some of those 0.1uf DIP caps that are all over every >> board. >> >> -- >> Jim Yanik >> jyanik >> at >> kua.net > > trace is solid , no trace problems . Is that a trace with a signal displayed,or just the baseline trace? With a signal displayed,you can see any horiz jitter. Without an input signal,you can't see any jitter in the horiz. > > and one thing i noticed , when i control the read out intensity fully > CW , the R-O shifts upwards ... > > I wonder if your CRT is maxed out on intensity.(grid bias) -- Jim Yanik jyanik at kua.net
From: NetSpid3r on 17 Nov 2007 05:53 On Nov 17, 3:08 am, Jim Yanik <jya...(a)abuse.gov> wrote: > "NetSpi...(a)gmail.com" <NetSpi...(a)gmail.com> wrote innews:28ac4545-7a53-4594-83d8-910b6ccf1d63(a)e4g2000hsg.googlegroups.com: > > > > > On Nov 16, 6:57 am, Jim Yanik <jya...(a)abuse.gov> wrote: > >> "NetSpi...(a)gmail.com" <NetSpi...(a)gmail.com> wrote in > >> news:19dc4e5b-d326- > >> 4c17-9bc9-bb21fa6f0...(a)a28g2000hsc.googlegroups.com: > > >> > Jim Yanik wrote: > >> >> "NetSpi...(a)gmail.com" <NetSpi...(a)gmail.com> wrote in > >> >>news:1195075563.961231.101880(a)57g2000hsv.googlegroups.com: > > >> >> >http://video.yahoo.com/video/play?vid=1466538 > > >> >> > The readout looks bad , i can see jumpy dots ,instead of clear > >> >> > numbers as in the other 2445 . > >> >> > i replaced those 3 47uf caps on the A5 board (control board) , > >> >> > and it didn't helped . > >> >> >http://img110.imageshack.us/img110/2372/image015pn5.jpg > > >> >> 2445 non-B scopes have separate R-O boards. > >> >> the signal from them feeds into the vertical on the main bottom > >> >> board. try swapping the readout boards. > >> >> IIRC,there's also a pot to adjust R-O crawl/jitter. > >> >> see the cal procedure in your service manual. > > >> >> On "B" models,the readout is integrated to the A5 uP board. > >> >> "B" model A5 uP boards are NOT swappable with earlier versions. > > >> >> -- > >> >> Jim Yanik > >> >> jyanik > >> >> at > >> >> kua.net > >> > tried play with jitter , didn't do the trick ... > > >> > and you are right about A5 in the 2445 , the R-O is not on this > >> > board , i just did a swap with a good 2445 A5 and got the same > >> > jerky readout . > > >> > what component is making the problem in the R-O of the 2445 ? > >> > caps ? or something else ? > > >> possibly caps,or a bad hybrid on the main board. > >> Does it twitch in the vert or horiz direction,or both? signal trace > >> solid,in both V and H axes? > >> This may be where you have to scope every decoupled PS supply line. > >> could even be some of those 0.1uf DIP caps that are all over every > >> board. > > >> -- > >> Jim Yanik > >> jyanik > >> at > >> kua.net > > > trace is solid , no trace problems . > > Is that a trace with a signal displayed,or just the baseline trace? > With a signal displayed,you can see any horiz jitter. > Without an input signal,you can't see any jitter in the horiz. > > > > > and one thing i noticed , when i control the read out intensity fully > > CW , the R-O shifts upwards ... > > I wonder if your CRT is maxed out on intensity.(grid bias) > > -- > Jim Yanik > jyanik > at > kua.net i'l try with a signal later on ... and i adjusted the grid bias , its fine .
From: NetSpid3r on 18 Nov 2007 16:24 On Nov 17, 3:08 am, Jim Yanik <jya...(a)abuse.gov> wrote: > "NetSpi...(a)gmail.com" <NetSpi...(a)gmail.com> wrote innews:28ac4545-7a53-4594-83d8-910b6ccf1d63(a)e4g2000hsg.googlegroups.com: > > > > > On Nov 16, 6:57 am, Jim Yanik <jya...(a)abuse.gov> wrote: > >> "NetSpi...(a)gmail.com" <NetSpi...(a)gmail.com> wrote in > >> news:19dc4e5b-d326- > >> 4c17-9bc9-bb21fa6f0...(a)a28g2000hsc.googlegroups.com: > > >> > Jim Yanik wrote: > >> >> "NetSpi...(a)gmail.com" <NetSpi...(a)gmail.com> wrote in > >> >>news:1195075563.961231.101880(a)57g2000hsv.googlegroups.com: > > >> >> >http://video.yahoo.com/video/play?vid=1466538 > > >> >> > The readout looks bad , i can see jumpy dots ,instead of clear > >> >> > numbers as in the other 2445 . > >> >> > i replaced those 3 47uf caps on the A5 board (control board) , > >> >> > and it didn't helped . > >> >> >http://img110.imageshack.us/img110/2372/image015pn5.jpg > > >> >> 2445 non-B scopes have separate R-O boards. > >> >> the signal from them feeds into the vertical on the main bottom > >> >> board. try swapping the readout boards. > >> >> IIRC,there's also a pot to adjust R-O crawl/jitter. > >> >> see the cal procedure in your service manual. > > >> >> On "B" models,the readout is integrated to the A5 uP board. > >> >> "B" model A5 uP boards are NOT swappable with earlier versions. > > >> >> -- > >> >> Jim Yanik > >> >> jyanik > >> >> at > >> >> kua.net > >> > tried play with jitter , didn't do the trick ... > > >> > and you are right about A5 in the 2445 , the R-O is not on this > >> > board , i just did a swap with a good 2445 A5 and got the same > >> > jerky readout . > > >> > what component is making the problem in the R-O of the 2445 ? > >> > caps ? or something else ? > > >> possibly caps,or a bad hybrid on the main board. > >> Does it twitch in the vert or horiz direction,or both? signal trace > >> solid,in both V and H axes? > >> This may be where you have to scope every decoupled PS supply line. > >> could even be some of those 0.1uf DIP caps that are all over every > >> board. > > >> -- > >> Jim Yanik > >> jyanik > >> at > >> kua.net > > > trace is solid , no trace problems . > > Is that a trace with a signal displayed,or just the baseline trace? > With a signal displayed,you can see any horiz jitter. > Without an input signal,you can't see any jitter in the horiz. > > > > > and one thing i noticed , when i control the read out intensity fully > > CW , the R-O shifts upwards ... > > I wonder if your CRT is maxed out on intensity.(grid bias) > > -- > Jim Yanik > jyanik > at > kua.net Well , the read-out is good now , i replaced the power supply , and don't have jerky read-out . i guess power supply ain't that good . but i got another problem with this scope , the horiz is not good at some of time bases , some of them ok , but lets say 5u is drifting . i did CAL 01-04 , but got LIMIT warning in the horiz section , could not adjust as required . something is wrong , what i'm doing wrong ?
From: Jim Yanik on 18 Nov 2007 17:33
"NetSpid3r(a)gmail.com" <NetSpid3r(a)gmail.com> wrote in news:a089d234-8202-4980-a6d9-ae53bee0e1b7(a)41g2000hsh.googlegroups.com: > On Nov 17, 3:08 am, Jim Yanik <jya...(a)abuse.gov> wrote: >> "NetSpi...(a)gmail.com" <NetSpi...(a)gmail.com> wrote >> innews:28ac4545-7a53-4594-83d8-910b6ccf1d63(a)e4g2000hsg.googlegroups.co >> m: >> >> >> >> > On Nov 16, 6:57 am, Jim Yanik <jya...(a)abuse.gov> wrote: >> >> "NetSpi...(a)gmail.com" <NetSpi...(a)gmail.com> wrote in >> >> news:19dc4e5b-d326- >> >> 4c17-9bc9-bb21fa6f0...(a)a28g2000hsc.googlegroups.com: >> >> >> > Jim Yanik wrote: >> >> >> "NetSpi...(a)gmail.com" <NetSpi...(a)gmail.com> wrote in >> >> >>news:1195075563.961231.101880(a)57g2000hsv.googlegroups.com: >> >> >> >> >http://video.yahoo.com/video/play?vid=1466538 >> >> >> >> > The readout looks bad , i can see jumpy dots ,instead of >> >> >> > clear numbers as in the other 2445 . >> >> >> > i replaced those 3 47uf caps on the A5 board (control board) >> >> >> > , and it didn't helped . >> >> >> >http://img110.imageshack.us/img110/2372/image015pn5.jpg >> >> >> >> 2445 non-B scopes have separate R-O boards. >> >> >> the signal from them feeds into the vertical on the main bottom >> >> >> board. try swapping the readout boards. >> >> >> IIRC,there's also a pot to adjust R-O crawl/jitter. >> >> >> see the cal procedure in your service manual. >> >> >> >> On "B" models,the readout is integrated to the A5 uP board. >> >> >> "B" model A5 uP boards are NOT swappable with earlier versions. >> >> >> >> -- >> >> >> Jim Yanik >> >> >> jyanik >> >> >> at >> >> >> kua.net >> >> > tried play with jitter , didn't do the trick ... >> >> >> > and you are right about A5 in the 2445 , the R-O is not on this >> >> > board , i just did a swap with a good 2445 A5 and got the same >> >> > jerky readout . >> >> >> > what component is making the problem in the R-O of the 2445 ? >> >> > caps ? or something else ? >> >> >> possibly caps,or a bad hybrid on the main board. >> >> Does it twitch in the vert or horiz direction,or both? signal >> >> trace solid,in both V and H axes? >> >> This may be where you have to scope every decoupled PS supply >> >> line. could even be some of those 0.1uf DIP caps that are all over >> >> every board. >> >> >> -- >> >> Jim Yanik >> >> jyanik >> >> at >> >> kua.net >> >> > trace is solid , no trace problems . >> >> Is that a trace with a signal displayed,or just the baseline trace? >> With a signal displayed,you can see any horiz jitter. >> Without an input signal,you can't see any jitter in the horiz. >> >> >> >> > and one thing i noticed , when i control the read out intensity >> > fully CW , the R-O shifts upwards ... >> >> I wonder if your CRT is maxed out on intensity.(grid bias) >> >> -- >> Jim Yanik >> jyanik >> at >> kua.net > > Well , the read-out is good now , i replaced the power supply , and > don't have jerky read-out . > i guess power supply ain't that good . probably marginal electrolytics,bad ESR. often,the PS is the source of trouble appearing elsewhere. > > but i got another problem with this scope , the horiz is not good at > some of time bases , some of them ok , but lets say 5u is drifting . > i did CAL 01-04 , but got LIMIT warning in the horiz section , could > not adjust as required . > something is wrong , what i'm doing wrong ? > All the parts for timing are on the sweep hybrids.try swapping the A and B sweep hybrids,and recal.if the problem goes away on that range/mode,then yu have a bad hybrid. -- Jim Yanik jyanik at kua.net |