Correct power plug for Elite BVP4+?

[BarryTheCrab]

Good grief, I just got my Elite refurbed and on the way out the shop door I dropped the
power plug and aint gravity a bitch...
So, where can I get a proper power plug but not get porked like at TGrant?
I ordered one from Amazon but LordSmurf says it is the wrong one.
LS is having to attend to personal things at the moment so I dare not ask him.
Attached is the broken item for reference.

[dpalomaki]

As you have seen you can find supplies on Amazon.com for a wide variety of prices.

Note that in theory buying an exact replacement is often best because it should be matched to the BVP4 with respect to power supply filtering. Apparently the BVP-4s are sensitive to the "noise" that is often found on the output of many generic power adapters from China - words on TGrant's site and what you heard from LS imply it is an issue.
Consider this old thread:
http://www.digitalfaq.com/forum/vcr-...deo-power.html

With respect to TGrant's prices, you are paying him for convenience - researching, buying, stocking, packing and shipping it to you. But then you can DIY and assume the risk of getting it wrong or getting one that only sort of works.

[BarryTheCrab]

The gentleman that repaired/refurbed my BVP4+ has PS for me, for free.
He is aware of the needs.
And I may have been a little harsh on TGrant, but just a little!

[dpalomaki]

Please let us know what it is and how well it works.

Others may be looking for one.

[lordsmurf]

It needs to be the AT&T low ripple unit, for best experience. I probably have an extra.

I'll always tell others what PSUs to get for their TBCs, etc, as I have that info for many items. And it's something I hope to add to the new site platforms. Most PSUs are in the $10-20 range, shipped/taxed. The quality units are rarely bad, just the junky Chinese knockoffs.

In the past, I've caught TGrant supplying low quality Chinese junk supplies, so you're overpaying for $4 eBay/Amazon Chinese garbage. Be aware of "for" supplies ("for" this, "for" that, be it model or quality PSU or an item). I don't see how he can claim these are tested, as image/audio noise happens, the units buzz, workflow power noise added, etc.

I want to hear the outcome of this repair/refurb sometime. I have a non-working unit here, just B&W output. Just not now, I have family things to tend to, as you mention.

[BarryTheCrab]

LS and others,
I am eager to test the unit and will share results.
The gentleman that did the repair stresses it was fun and a challenge but is not setup to do this type of niche repairs
especially those that would require a mailing aspect as he has no staff, no mailroom, and is already in demand locally.
That being said he seemed positive in perhaps sharing what he learned.
The test is on hold of course!

[dpalomaki]

Interesting. That power supply reads "transformer" and is single voltage input (120 volts) implying it is not a switching supply. (It might be as simple as a single diode half-wave, or a two-diode center tapped or 4-diode bridge full-wave rectifier.

In what way did the supply break when it fell? If a simple cracked case or broken solder joint it might be repairable.

Subject to line voltage variations one can expect to see about 17 VDC at the output of a simple rectifier circuit driven by a 12VAC transformer under no load conditions.

The transformer supply output noise will typically be 60 Hz harmonics while the switching mode supply will be 60 Hz harmonics plus what ever much higher frequency garbage the switching circuits add.

[lordsmurf]

Disregard.

That was not the proper supply. In fact, impossible. The image shown is center-negative. The BVP needs center-positive. That PSU goes to a AVT-8710, and was the OEM model from the black era.
The BVP4/4+ use AT&T low-ripple PSUs, and was the OEM.

[BarryTheCrab]

The one I dropped was tested by the tech and functions.
It has a rattle inside and I will replace it, but it works.
My electrical knowledge stops at the light switch so I’m thrilled to have both my tech and this community to guide me.

[dpalomaki]

FWIW: The back panel of my BVP-4 power jack is labeled 12 DC, 500 ma, center negative!

I also have a Panasonic KX-A11 power supply (center negative, 12 VDC, 500 ma) that I believe came with it.

Consistent with the discussions in this old thread
http://www.digitalfaq.com/forum/vcr-...deo-power.html

The rattle can probably be fixed, likely some broken plastic that held a transformer in place.

[lordsmurf]

Memory fails me.

Panasonic KX-A11 is the unit I'm thinking of.
That CUI is still the OEM from AVT-8710, however.

[dpalomaki]

As a matter of interest I ran some quick tests on a BVP-4 Power supply; i.e., the KX-A11.
The supply is rated for 12 VDC 500 ma at 120 VAC input.
The output appears to be full wave rectified DC with 120 Hz saw tooth waveform ripple.
The following voltage and ripple were measured at various resistance loads.
Waveform observed on an oscilloscope.

AMPS - VDC - VAC ripple
0.00 - 18.5 - 0.003 (only meter & 'scope load ~ 5 meg ohm/)
0,10 - 16,1 - 0.20
0.39 - 13.1 - 0,62
0.45 - 12.1 - 0.66
0.52 - 11.7 - 0.74

No significant high frequency noise noted on the waveform - only the expected saw tooth wave.
AC line voltage was about 121 volts at the time of the test.

For comparison I looked at the output of a generic 12 VDC 1 amp 100-240 VAC switching supply.
At 0.35 amps resistance load the output was 11.9 VDC with ripple at around 75 kHz but varying, with a lot of high frequency (~ 2 mHz and beyond) garbage on the waveform. This ripple ran about 1.0 v p-p. This type of supply would require excellent filtering/isolation in the unit it powers (and in nearby units and leads as well).

[RobustReviews]

Quote:

Originally Posted by dpalomaki

As a matter of interest I ran some quick tests on a BVP-4 Power supply; i.e., the KX-A11.
The supply is rated for 12 VDC 500 ma at 120 VAC input.
The output appears to be full wave rectified DC with 120 Hz saw tooth waveform ripple.
The following voltage and ripple were measured at various resistance loads.
Waveform observed on an oscilloscope.

AMPS - VDC - VAC ripple
0.00 - 18.5 - 0.003 (only meter & 'scope load ~ 5 meg ohm/)
0,10 - 16,1 - 0.20
0.39 - 13.1 - 0,62
0.45 - 12.1 - 0.66
0.52 - 11.7 - 0.74

No significant high frequency noise noted on the waveform - only the expected saw tooth wave.
AC line voltage was about 121 volts at the time of the test.

For comparison I looked at the output of a generic 12 VDC 1 amp 100-240 VAC switching supply.
At 0.35 amps resistance load the output was 11.9 VDC with ripple at around 75 kHz but varying, with a lot of high frequency (~ 2 mHz and beyond) garbage on the waveform. This ripple ran about 1.0 v p-p. This type of supply would require excellent filtering/isolation in the unit it powers (and in nearby units and leads as well).

Interesting, I imagine this is linear by your description?

2MHz is a touch curious, I wonder where that is coming from? Diode noise or winding? Who knows, it doesn't matter and is probably not worth investigating further unless you have literally nothing better to do! As a ham' that's right in the sort of region that would drive me mad!

[dpalomaki]

As a ham the wave forms from the low cost from-China generic may interest you.
These are from a storage scope in single sweep mode to capture several samples.
The 'scope used a 10x probe and was AC coupled.

The ripple garbage varies over time as seen in the SDS00004 file slow scan. The ...01 and ...03 files are representative captures of the detailed switching noise. A lot of the crud is at SD video frequencies. The high frequency looks like ringing in the switching adapter. It has a ferrite core on the output lead but that doesn't clean it up.

I think a few take-aways from this is are:
- switching supplies can out out a lot of noise and much can be at high frequencies. It will likely depend on the design of the specific supply under consideration.
- transformer-based supplies may have much lower noise at high frequencies but can have ripple at harmonics of line (mains) frequencies.
- It is safest to use the power supply that was furnished with the gear, or an exact replacement. Equal voltage and current ratings are no assurance of equal performance from a noise standpoint.
- my test was with two specific supplies, other supplies may have different performance characteristics.

FWIW:The switching supply I tested was labeled Model CJ-1210, made in China.

[BarryTheCrab]

Well, good heavens.
I'm happy to have triggered such a thorough response from this amazing community.
Such a pity I have not a clue what the fricnfrac any of it means!
My rattling plug still works, and the BVP4+ is behaving as far as my limited time has allowed me to test it.
Though I will refer back to this thread when polishing off my doctoral thesis…

[RobustReviews]

Quote:

Originally Posted by dpalomaki

As a ham the wave forms from the low cost from-China generic may interest you.
These are from a storage scope in single sweep mode to capture several samples.
The 'scope used a 10x probe and was AC coupled.

The ripple garbage varies over time as seen in the SDS00004 file slow scan. The ...01 and ...03 files are representative captures of the detailed switching noise. A lot of the crud is at SD video frequencies. The high frequency looks like ringing in the switching adapter. It has a ferrite core on the output lead but that doesn't clean it up.

I think a few take-aways from this is are:
- switching supplies can out out a lot of noise and much can be at high frequencies. It will likely depend on the design of the specific supply under consideration.
- transformer-based supplies may have much lower noise at high frequencies but can have ripple at harmonics of line (mains) frequencies.
- It is safest to use the power supply that was furnished with the gear, or an exact replacement. Equal voltage and current ratings are no assurance of equal performance from a noise standpoint.
- my test was with two specific supplies, other supplies may have different performance characteristics.

FWIW:The switching supply I tested was labeled Model CJ-1210, made in China.

Very interesting, I'll have a proper look when I'm back at the desktop, mobile view isn't the best to digest these. One looks like classic ringing, I have seen the 'add a ferrite' crew just think that all ferrites are all equal, I guess it may be the ferrite isn't suitable for these frequencies?

I'm not keen on just using 'any random' SMPS in video circuits and I'm very 'unkeen' on manufacturers like JVC who left them unshielded on the main PCB. Power supply isn't my forté and JVC et. al. sold millions of them so there can't be that much wrong with it, however, it just doesn't sit easy with me for RF equipment.

This is why I'm not a cheerleader for UPS' as budget models designed for home IT equipment have a nasty habit of spewing this sort of RF garbage. Each to their own though, and I'm not here to tell people what to do, but I'm cautious about using a cheapo UPS in video circuits precisely due to this issue.

Seems a bit bizarre to worry about low-noise power supplies and then plug them into a huge, nasty SMPS.... I can't speak as to every model though and every situation.

My route into electronics is through instrumentation (ion-selective mostly) where the difference in the measurement signal of pV can cause errors - that's why my mind goes in that direction no doubt; you won't find sensitive electronics connected to $200 UPS units that's certain.

[dpalomaki]

Tried an "Archer" (AKA Radio Shack) cast no 273-1652B Ac adapter. Output is 12 VDC, 500 MA from 120 volt input. This is a transformer-based supply, one can tell my the weight. It measured 10.9 volts at .34 amps with 0.28 volts 120 Hz saw tooth ripple. (All Voltages RMS unless stated otherwise and measured with a Fluke 89 IV meter.) No surprise there.

Tried the switching mode power supply that came with a BMD ANALOG to SDI converter. It is rated 12 VDC at 0.84 amps It put out 11.9 VDC at .35 amps with 7 mV RMS ripple, and the waveform had about 70 mV peak-to-peak. Much cleaner than the generic I tested.

That shows it is possible to design better SMPS, and that the SMPS selected can make a difference even if the volt and amp ratings are the same.