Re: Flyback Troubleshooting help (Solved!)

Jess Askey wrote:
> Okay, I have a resolution to this problem... just a few more
> breadcrumbs of info...All the previous messages in this thread ended
> up concluding that the flyback was probably good.
>
> 1. I double checked all other components around the HOT on the PCB
> or put in new ones
> 2. After all of that I still had the supply shutdown due to overload.
>
> I spoke to Mark Shostak about the Cinelabs replacement he did on the
> Vector HV transformer. His comments were...
>
> * The Amplifone 'ultra-tuned' transformers are extremely finicky
> about any inductive abnormalities
> * When in doubt, it is highly likely that the transformer is the
> problem
>
> So, I found that I had some flybacks from a WG K7000 monitor laying
> around. I thought I would try hooking up the primary only of it to the
> Amplifone and see what happens. Well, the board came up fine and I had
> decent 24VAC on one of the secondaries.
>
> Conclusions:
>
> 1. the Amplifone Raster Flyback *is* bad even tho it rings (I think
> I had at least 7 solid ring pulses)
> 2. The Wells-Gardner K7000 flyback might work as a suitable
> replacement with PCB modifications, it has all the voltage taps
> (filament, +24, +15, +180, focus, screen, anode) that the
> amplifone uses.
>
> Im going to see if I can get the K7000 flyback working fully this
> weekend and will report back.
>
> jess
>
Hi Jess,

Interesting news, I would like to borrow one of your bad HV transformers
to test with my LOPT/Flyback ring checker to see what it thinks...

As for substituting, be sure to check the High Tension voltage - you
really do not want this to be any higher than around 18KV...

John :-#)#
>
>
> On 1/19/2011 12:12 AM, Jess Askey wrote:
>> Well, I put the flyback back in and removed the following loads...
>>
>> 1. 180V Secondary - Pulled rectifier diode
>> 2. Filament - Pulled current limiting resistor
>> 3. 24V Secondary - Pulled rectifier diode
>> 4. Focus Tap - Disconnected and insulated
>> 5. Anode - Disconnected and insulated
>>
>> Unfortunately, after all this the switcher still shuts down due to
>> overcurrent. I tried disconnecting the deflection coil and it took
>> about a half second longer to shutdown but still did. So, that pretty
>> much removes the faults being related too ...
>>
>> 1. Bad Picture Tube
>> 2. Overload on Secondary Windings
>> 3. Deflection Coil Support Circuitry (deflection capacitor and
>> some inductors)
>>
>> Pretty much the only thing left is right around the HOT at this
>> point. (2,3 and 5 'test' okay tho)
>>
>> 1. HOT Discharge Capacitor (.1 @ 1600V)
>> 2. HOT Protection Diode (0.8A 1500V rectifier)
>> 3. HOT (BU-208)
>> 4. T1 - HOT Driver Transformer
>> 5. Q9 - Driver Transistor (D40P5)
>>
>> I am going to have to order these parts... just so I have known good
>> ones on hand. I am using a BU-207 in one of my PCB's which should be
>> okay, it just can't handle the same power, which isn't a problem in
>> the 1 second it runs before shutdown.
>>
>> I started scoping around the HOT (base side) and T1 and the waveforms
>> get pretty distorted away from a square wave. I can post pics of
>> those if anyone is interested (still). :-)
>>
>> jess
>>
>> PS - I got some feedback from Mark @ Cinelabs that the Amplifone
>> 'Ultra-Tuned' transformers are super finicky since they rely on
>> ferro-resonance.... after doing some searching... this is explained
>> in this patent from 1975 which explains this approach.. perhaps these
>> flybacks are a bit different beasts??
>> http://www.google.com/patents?hl=en&lr=&vid=USPAT3868538&id=N_o1AAAAEBAJ&oi=fnd&dq=ferro+resonant+flyback&printsec=abstract#v=onepage&q=ferro%20resonant%20flyback&f=false
>>
>>
>>
>>
>> On 1/18/2011 9:48 AM, John Robertson wrote:
>>> Jess Askey wrote:
>>>> Okay, this is looking better now....
>>>>
>>>> This is the best I could lock onto the ringing at the tip of the
>>>> main pulse... this is *very* zoomed in (.2us/div) and I couldn't
>>>> quite get it to trigger ahead of the main pulse. Apologies for the
>>>> crappy lighting...
>>>>
>>>> http://gamearchive.askey.org/Video_Games/Manufacturers/Atari/monitors/amplifone/raster/images/secondary_ring_15k.jpg
>>>>
>>>> .... but is exactly what I should see. This is pulled off one of
>>>> the secondaries.
>>>>
>>>> Additionally: I was feeding my primary with 10VPP. Upon measuring
>>>> my secondaries, they all came out just about right comparing to the
>>>> computed ratios from 120V down to 10V. I even had a whopping 50VDC
>>>> on my anode.
>>>>
>>>> So: Seems this transformer must be good. Pretty exciting that I had
>>>> it taken apart to the extent that I did and managed to get to back
>>>> together (quite easily too). I will re-silicone it tomorrow and
>>>> move back to troubleshooting the support circuitry. Since I have
>>>> another flyback and my test rig is stable, I will ring that one
>>>> tomorrow too and then report back.
>>>>
>>>> Has anyone run into either the deflection capacitor or the retrace
>>>> capacitor breaking down at operating voltages? I still can't
>>>> believe that I have two PCB's with the same problem. Shit, maybe my
>>>> picture tube has a short? Can I run a flyback with the Anode and
>>>> focus disconnected?
>>>>
>>>> thanks for staying late at the party!!
>>>>
>>>> jess
>>>>
>>>
>>> Hi Jess,
>>>
>>> I realized the reason you weren't seeing any ringing was the core
>>> was outside of the coil so at that point all you had was a coil -
>>> with the core in place then you would get the ringing you show
>>> today. Figured this out after going to bed last night...
>>>
>>> As for running the flyback with no load on the Anode and focus lines
>>> - no problem, I do this all the time. I have a ceramic cup on my
>>> test bench that I stick the anode cap into when I am testing chassis
>>> to avoid ouchies.
>>>
>>> John :-#)#
>>>>
>>>> On 1/17/2011 5:27 PM, John Robertson wrote:
>>>>> Jess Askey wrote:
>>>>>> Here is the main primary being rung @ 15KHz with a .047uf cap in
>>>>>> series with it, there are no other windings on the core with
>>>>>> it... but I can throw more on if needed.
>>>>>>
>>>>>> http://gamearchive.askey.org/Video_Games/Manufacturers/Atari/monitors/amplifone/raster/images/main_primary_ring_no_secondaries.jpg
>>>>>>
>>>>>> I thought that Raster flybacks where supposed to have spacers
>>>>>> between the cores? This one doesn't have any.
>>>>>>
>>>>>> jess
>>>>>>
>>>>>
>>>>> That image does not look good to me, the signal is damped way too
>>>>> quickly. You should see a train of decreasing rings like the other
>>>>> picture you posted. I suspect the red coil has a shorted winding
>>>>> after all - assuming you are only driving the red coil and it is
>>>>> out of circuit as in your most recent picture above.
>>>>>
>>>>> As for the spacer, it all depends on the design. I am fairly sure
>>>>> most flybacks do NOT have a spacer between the two halves, what
>>>>> they usually do have is some sort of glue...
>>>>>
>>>>> John :-#(#
>>>>>>
>>>>>> On 1/17/2011 2:35 PM, Rodger Boots wrote:
>>>>>>> Just grab a capacitor (.1 to 1 uF or so) and put it in series
>>>>>>> with the generator output. You just need to get rid of the DC
>>>>>>> component of the signal (transformers get weird around DC).
>>>>>>>
>>>>>>>
>>>>>>> On Mon, Jan 17, 2011 at 3:19 PM, Jess Askey <jess@askey.org
>>>>>>> <mailto:jess@askey.org>> wrote:
>>>>>>>
>>>>>>> My generator doesn't have a DC offset, I will have to build
>>>>>>> one. I just have a waveform generator IC that I breadboarded
>>>>>>> up really quick... I will see if I can get a waveform
>>>>>>> generator locally that has that feature.
>>>>>>>
>>>>>>>
>>>>>>> On 1/17/2011 2:16 PM, Rodger Boots wrote:
>>>>>>>> Does your generator have a knob marked "DC offset"? If so,
>>>>>>>> set it for a -4 to +4 volt square wave. Using 0 to +8
>>>>>>>> volts isn't going to give you useful readings.
>>>>>>>>
>>>>>>>>
>>>>>>>> On Mon, Jan 17, 2011 at 2:19 PM, Jess Askey <jess@askey.org
>>>>>>>> <mailto:jess@askey.org>> wrote:
>>>>>>>>
>>>>>>>> Okay, I put the standalone LOPT onto my square wave
>>>>>>>> generator (unfortunately my generator can only supply
>>>>>>>> 30ma) so Im not sure that is enough.
>>>>>>>>
>>>>>>>> Here is the signal before attaching the LOPT.... 15KHz
>>>>>>>> 9vP-P
>>>>>>>>
>>>>>>>> http://gamearchive.askey.org/Video_Games/Manufacturers/Atari/monitors/amplifone/raster/images/generator_output_15k.jpg
>>>>>>>>
>>>>>>>> Here is the primary with that signal attached...
>>>>>>>> secondaries are exactly the same waveform, yet in
>>>>>>>> different ratios (and those ratios are not correct)
>>>>>>>>
>>>>>>>> http://gamearchive.askey.org/Video_Games/Manufacturers/Atari/monitors/amplifone/raster/images/lopt_ringing_15k.jpg
>>>>>>>>
>>>>>>>> Doesn't look right.
>>>>>>>>
>>>>>>>> When I read a DC voltage on the Anode cap, I have
>>>>>>>> 2.2VDC, pretty low. :-(
>>>>>>>>
>>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
>>>>> Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, VideoGames)
>>>>> www.flippers.com
>>>>> "Old pinballers never die, they just flip out"
>>>>>
>>>
>>>
>>> --
>>> John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
>>> Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, VideoGames)
>>> www.flippers.com
>>> "Old pinballers never die, they just flip out"
>>>

---------------------------------------------------------------------------
** Unsubscribe, subscribe, or view the archives at http://www.vectorlist.org
** Please direct other questions, comments, or problems to chris@westnet.com
Received on Thu Jan 20 17:44:31 2011