Re: Oscilloscope Recommendation

I've almost always used TEK scopes, and liked them. What ever you choose, see if they will cut you a good deal for being a educational or non-profit. A lot of companies will, especially on a discontinued model. On Sat, Apr 29, 2017 at 6:15 PM, Michael Thompson via cctech < cct...@classiccmp.org>

Re: Oscilloscope Recommendation

Thanks for the recommendation Sent from my iPhone > On Apr 29, 2017, at 4:30 PM, allison wrote: > >> On 04/29/2017 01:28 PM, Michael Thompson via cctech wrote: >> The RICM just received $1,000 to buy a new oscilloscope. I would like a >> four channel. and color

Re: Oscilloscope Recommendation

If it is your only scope I recommend an analog scope of at least 100 MHz, with dual trace and delayed sweep. If you already have an analog scope, I recommend a logic analyzer instead of a digital scope. If you already have both above, I recommend a digital scope. Dwight

Re: Oscilloscope Recommendation

On 04/29/2017 01:28 PM, Michael Thompson via cctech wrote: > The RICM just received $1,000 to buy a new oscilloscope. I would like a > four channel. and color would also be nice. The bandwidth doesn't need to > be high because we usually work on ancient equipment. > > What would you suggest? > I

Re: Reviving VT220?

> Since it doesn't smoke, I'm thinking the horizontal sweep > transistor may have gone out. It may have shorted, which > then may have burned up the primary winding in the flyback > (if left on long enough). I'd check that transistor for a > short, and then you can trace a few traces to identify

Re: Oscilloscope Recommendation

On 4/29/2017 10:59 AM, Jon Elson via cctech wrote: On 04/29/2017 12:28 PM, Michael Thompson via cctech wrote: The RICM just received $1,000 to buy a new oscilloscope. I would like a four channel. and color would also be nice. The bandwidth doesn't need to be high because we usually work on

Re: Oscilloscope Recommendation

> On Apr 29, 2017, at 12:53, Chuck Guzis via cctech > wrote: > >> On 04/29/2017 10:28 AM, Michael Thompson via cctech wrote: >> The RICM just received $1,000 to buy a new oscilloscope. I would like >> a four channel. and color would also be nice. The bandwidth doesn't >>

Re: Oscilloscope Recommendation

On 04/29/2017 12:28 PM, Michael Thompson via cctech wrote: The RICM just received $1,000 to buy a new oscilloscope. I would like a four channel. and color would also be nice. The bandwidth doesn't need to be high because we usually work on ancient equipment. What would you suggest? Really NEW,

Re: Oscilloscope Recommendation

I would suggest just about any used Tektronix TDS 200mhz or higher 4 channel scope with a good display- from the mid 90s or newer. Make sure to look up the model year to ensure it has reliable caps. I have not been a fan of the new designed-in-china test equipment like the 'rigol' On Sat, Apr

Oscilloscope Recommendation

The RICM just received $1,000 to buy a new oscilloscope. I would like a four channel. and color would also be nice. The bandwidth doesn't need to be high because we usually work on ancient equipment. What would you suggest? -- Michael Thompson

Re: Oscilloscope Recommendation

On 04/29/2017 10:28 AM, Michael Thompson via cctech wrote: > The RICM just received $1,000 to buy a new oscilloscope. I would like > a four channel. and color would also be nice. The bandwidth doesn't > need to be high because we usually work on ancient equipment. The Rigol scopes have the

Re: Oscilloscope Recommendation

The RICM just received $1,000 to buy a new oscilloscope. I would like a four channel. and color would also be nice. The bandwidth doesn't need to be high because we usually work on ancient equipment. What would you suggest? Siglent or Rigol are good bang for the buck. Rigol has a

Re: Reviving VT220?

The High Voltage capacitors 600 to 2,000 VDC have a finite life. Unless you checked for leakage or ESR be suspect of values in range. Since you are in the UK, Farnell/element14 may be the best parts distributor. ASC Metalized Polyester Film, 6 kVolts

Re: Reviving VT220?

Hi Jon, I can hear a light crackle but not a whine. Are you referring to Q202? The centre pin is 11v, the other two are at 0v. Thanks, Aaron Jon Elson writes: > On 04/29/2017 08:34 AM, Aaron Jackson via cctalk wrote: >> The heater and control pins appear to be giving sensible voltages. The

Re: HP 1331A X-Y display blanking

I don't but. If there is not a connector on the back, you will need to route the signal to one. Find the erase button and look at the voltages. The "erase" signal will either be grounded to function or will be raise to a voltage level +5 or +12 for example. Once you have that, all you need is a

FFS: Elgar IPS1100 UPS

Much of what used to be power-hungry connectivity hardware for me has gone low-power, so I'm scaling back my UPS setup some. I've got an Elgar IPS1100, nominally rated at 1KVA sine-wave continuous (9.2A 60 Hz 120VAC). It's a pretty good-sized UPS, with fan cooling. It takes 48V in SLA cells

Re: Reviving VT220?

On Sat, Apr 29, 2017 at 5:45 PM, Aaron Jackson wrote: > I have measured these again because I thought they seemed a bit > strange. I must have probed the wrong pad on the circuit board earlier > (my probes don't fit in the CRT header). > > Here are all the voltages and

Re: Reviving VT220?

I have measured these again because I thought they seemed a bit strange. I must have probed the wrong pad on the circuit board earlier (my probes don't fit in the CRT header). Here are all the voltages and they don't seem too promising: pin 1, green, 4.3v, should be 50v to 80v pin 2, yellow,

Re: HP 1331A X-Y display blanking

On 04/29/2017 10:31 AM, Pete Lancashire wrote: I don't but. If there is not a connector on the back, you will need to route the signal to one. Find the erase button and look at the voltages. The "erase" signal will either be grounded to function or will be raise to a voltage level +5 or +12 for

Re: Reviving VT220?

On Sat, Apr 29, 2017 at 4:44 PM, Aaron Jackson wrote: > Unfortunately I do not have an oscilloscope anymore. I've been trying to > find a cheap one on eBay for a few months but the prices seem very high > these days. I might be able to borrow one. For now I just have a

Re: Reviving VT220?

On 04/29/2017 08:34 AM, Aaron Jackson via cctalk wrote: The heater and control pins appear to be giving sensible voltages. The logic of the board is fine, I can type on the terminals keyboard and I get the correct characters on the other end of the serial cable. The PSU is putting out 31v which

Re: Reviving VT220?

Unfortunately I do not have an oscilloscope anymore. I've been trying to find a cheap one on eBay for a few months but the prices seem very high these days. I might be able to borrow one. For now I just have a true RMS multimeter. I've tried both extremes of the contrast and brightness but the

Re: Reviving VT220?

On Sat, Apr 29, 2017 at 4:19 PM, Aaron Jackson wrote: > Seems to be working fine as a terminal hooked up to the TV which is good > news. I am sure you are correct about me having made a measurement error > there... So the logic side is working. The problem is very likely

Re: Reviving VT220?

Seems to be working fine as a terminal hooked up to the TV which is good news. I am sure you are correct about me having made a measurement error there... I'll take another look at the schematics. Thanks again, Aaron. > On Sat, Apr 29, 2017 at 2:34 PM, Aaron Jackson

HP 1331A X-Y display blanking

Has anyone got a manual for an HP 1331A X-Y display? It's a storage-tube device, and I'm curious to know if there's a way of triggering the erase function remotely rather than having to physically prod the erase button on the front. The rear just has X-Y-Z inputs, and I *think* that X-Y are

Re: Reviving VT220?

On Sat, Apr 29, 2017 at 2:34 PM, Aaron Jackson wrote: > The heater and control pins appear to be giving sensible voltages. The > logic of the board is fine, I can type on the terminals keyboard and I > get the correct characters on the other end of the serial cable. The

Re: Reviving VT220?

The heater and control pins appear to be giving sensible voltages. The logic of the board is fine, I can type on the terminals keyboard and I get the correct characters on the other end of the serial cable. The PSU is putting out 31v which seems fine? I'm used to discharging the tube before