Re: Ill NLS MS-230 ---manual!
On 7/29/19 10:30 PM, Jim Brain via cctalk wrote: > On 7/29/2019 9:24 PM, allison via cctalk wrote: >> >> Since you replaced the batteries did you check the fuse? > Yep, good. >> Also the 4066s > Hmm, all mine are soldered in. Do you suggest I desolder and check? >> sometimes get cranky and/or the sockets. > Only one '00 has a socket. >> >> The tough fail would be the CRT. Check the heater pins with a multimeter >> to see if its open (unplug it as there is a transformer winding across >> it). > I'll check. >> Mine needed one when I got it but they were available then (1977) >> from NLS. Side effect of the hammer mechanic owner. Now it would be a >> hunt though old tube brokers. > Yep, I know that'd be the main issue, but I am hopeful it's something > less problematic. >> >> Allison > >
Re: Ill NLS MS-230
On 7/30/19 2:58 PM, Brent Hilpert via cctalk wrote: > On 2019-Jul-29, at 6:34 PM, Jim Brain via cctalk wrote: >> I have an ill NLS MS-230 Miniscope. Is there anyone on list that might be >> interested in getting it running for me? I'm willing pay for the privilege. >> I'd like to see the unit working, but I have no experience with analog >> scopes, and I'd rather just entrust it to someone who can see it to success. >> I did replace the batteries and let it charge for quite a while. The red >> LED lights up on the front when on, but no sign of a trace, even when fed a >> known good 1kHz wave. The CRT does not appear to be on. >> >> Anyone a fan of these units and might be interested in taking a look? > > > It's tempting but I'm across the border and some shipping distance away. > > Looking at the schematic (readily available online), it's fairly > straightforward. > If you're willing to spend a little time on it, you could do the basics and > check > for the power supply voltages as listed on the schematic. > > The power supply is essentially 3 stages: > 1) line -> charging circuit for the batteries, > 2) batt -> +5 regulator, > 3) +5 -> simple switching supply for +/-7V, +80V, +100V, -720V, 0.5V > heater, 12V for U11. > > With nothing on the CRT (esp with the intensity turned full up), suspicion > may fall around the little switching supply. > > A key point to note with 'scopes like this is the cathode/heater runs at high > negative voltage relative to GND, rather than the TV/monitor convention of > the anode running at high positive voltage. This is done so the amplifiers to > drive the electrostatic deflection plates can be be operated near GND level > rather than having to raise them way above GND. > > So according to the schematic the heater (acting as cathode; either pin) > should measure -720V relative to GND and there should be 0.6V across the two > heater pins. > U11 should have 12V across pins 14 & 7, but like the heater, it to is > floating at -720V below GND. > Read the manual as it has troubleshooting information and test points. If you follow that it will bring you to the fault very quickly I've not seen the switching converter fail but there are many parts of the regulators that can. Hint do yourself a favor and expand and print the schematic as at least B if not D size. it will be easier to follow. Allison
Re: Ill NLS MS-230
On 2019-Jul-29, at 6:34 PM, Jim Brain via cctalk wrote: > I have an ill NLS MS-230 Miniscope. Is there anyone on list that might be > interested in getting it running for me? I'm willing pay for the privilege. > I'd like to see the unit working, but I have no experience with analog > scopes, and I'd rather just entrust it to someone who can see it to success. > I did replace the batteries and let it charge for quite a while. The red LED > lights up on the front when on, but no sign of a trace, even when fed a known > good 1kHz wave. The CRT does not appear to be on. > > Anyone a fan of these units and might be interested in taking a look? It's tempting but I'm across the border and some shipping distance away. Looking at the schematic (readily available online), it's fairly straightforward. If you're willing to spend a little time on it, you could do the basics and check for the power supply voltages as listed on the schematic. The power supply is essentially 3 stages: 1) line -> charging circuit for the batteries, 2) batt -> +5 regulator, 3) +5 -> simple switching supply for +/-7V, +80V, +100V, -720V, 0.5V heater, 12V for U11. With nothing on the CRT (esp with the intensity turned full up), suspicion may fall around the little switching supply. A key point to note with 'scopes like this is the cathode/heater runs at high negative voltage relative to GND, rather than the TV/monitor convention of the anode running at high positive voltage. This is done so the amplifiers to drive the electrostatic deflection plates can be be operated near GND level rather than having to raise them way above GND. So according to the schematic the heater (acting as cathode; either pin) should measure -720V relative to GND and there should be 0.6V across the two heater pins. U11 should have 12V across pins 14 & 7, but like the heater, it to is floating at -720V below GND.
Re: Ill NLS MS-230
On 7/29/19 10:30 PM, Jim Brain via cctalk wrote: > On 7/29/2019 9:24 PM, allison via cctalk wrote: >> >> Since you replaced the batteries did you check the fuse? > Yep, good. THe batteries are charged? (about 6.6V or more full charge) >> Also the 4066s > Hmm, all mine are soldered in. Do you suggest I desolder and check? >> sometimes get cranky and/or the sockets. > Only one '00 has a socket. Check only socketed devices. Do not desolder unless you have good reason to believe the part is bad. Hint check for 5-6V on the power pins of the ICs. IF you have the manual, check for all the voltages. >> >> The tough fail would be the CRT. Check the heater pins with a multimeter >> to see if its open (unplug it as there is a transformer winding across >> it). > I'll check. >> Mine needed one when I got it but they were available then (1977) >> from NLS. Side effect of the hammer mechanic owner. Now it would be a >> hunt though old tube brokers. > Yep, I know that'd be the main issue, but I am hopeful it's something > less problematic. The only problem with the CRT is finding a replacement. THey may be more common than thought. Haven't checked in decades. Allison
Re: Ill NLS MS-230
On 7/29/2019 9:24 PM, allison via cctalk wrote: Since you replaced the batteries did you check the fuse? Yep, good. Also the 4066s Hmm, all mine are soldered in. Do you suggest I desolder and check? sometimes get cranky and/or the sockets. Only one '00 has a socket. The tough fail would be the CRT. Check the heater pins with a multimeter to see if its open (unplug it as there is a transformer winding across it). I'll check. Mine needed one when I got it but they were available then (1977) from NLS. Side effect of the hammer mechanic owner. Now it would be a hunt though old tube brokers. Yep, I know that'd be the main issue, but I am hopeful it's something less problematic. Allison -- Jim Brain br...@jbrain.com www.jbrain.com
Re: Ill NLS MS-230
On 7/29/19 9:34 PM, Jim Brain via cctalk wrote: > I have an ill NLS MS-230 Miniscope. Is there anyone on list that might > be interested in getting it running for me? I'm willing pay for the > privilege. I'd like to see the unit working, but I have no experience > with analog scopes, and I'd rather just entrust it to someone who can > see it to success. I did replace the batteries and let it charge for > quite a while. The red LED lights up on the front when on, but no sign > of a trace, even when fed a known good 1kHz wave. The CRT does not > appear to be on. > > Anyone a fan of these units and might be interested in taking a look? > > Jim > Jim, I have a MS15 miniscope that has been my backup since '77. Good tool and I got that one in "not working" condition. I've worked on a few MS-215s over the years. Right now I'm up to my eyes with stuff to do but but if no one answers you, maybe in the late fall (after October). If you don't have the manual its on BAMA and a few other sites. Since you replaced the batteries did you check the fuse? Also the 4066s sometimes get cranky and/or the sockets. The tough fail would be the CRT. Check the heater pins with a multimeter to see if its open (unplug it as there is a transformer winding across it). Mine needed one when I got it but they were available then (1977) from NLS. Side effect of the hammer mechanic owner. Now it would be a hunt though old tube brokers. Allison
Ill NLS MS-230
I have an ill NLS MS-230 Miniscope. Is there anyone on list that might be interested in getting it running for me? I'm willing pay for the privilege. I'd like to see the unit working, but I have no experience with analog scopes, and I'd rather just entrust it to someone who can see it to success. I did replace the batteries and let it charge for quite a while. The red LED lights up on the front when on, but no sign of a trace, even when fed a known good 1kHz wave. The CRT does not appear to be on. Anyone a fan of these units and might be interested in taking a look? Jim -- Jim Brain br...@jbrain.com www.jbrain.com
