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Psk06 Or Psk08 Power Supply?


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HI,

Further to my earlier thread here http://www.dtvforum....wtopic=96123 , my PSK08 power supply seems to be on the way out (Ive taken it apart and its seems theres a bit of corrosion inside).

From what I have read I have head that the DC adapters can cause this and it may be better to go for an AC based adapter (PSK08).

What are peoples thoughts?

Thanks

Edited by Rambler
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Sometimes it can depend on what amp you've got as to which PS suits.

Have you changed your wallplate rambler-often the old saddle and screw soldiered wallplates can turn into power blockers over time!

I these days solely use psk08 as it will power old 22v amps when I am doing service calls for customers who have moved into a new house and have no signal. Never had a problem with AC!

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my PSK08 power supply seems to be on the way out (Ive taken it apart and its seems theres a bit of corrosion inside).

Typo there. Think you mean PSK06

From what I have read I have head that the DC adapters can cause this and it may be better to go for an AC based adapter (PSK08).

What are peoples thoughts?

Whatever. Not sure what part of your current power supply has the corrosion. Is it the actual injector portion? If so, I'd be looking for possible reasons of moisture ingress, rather than differences between AC/DC power injectors.

I prefer DC, since AC injectors can sometimes, in rare instances, cause weird reception problems.

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I these days solely use psk08 as it will power old 22v amps when I am doing service calls for customers who have moved into a new house and have no signal. Never had a problem with AC!

In situations like this, I would be inspecting the reception components to:

1) Match the power supply to masthead/distribution amplifier in use.

(There are DC only mastheads out there.)

2) Give a report on the condition of the installation.

3) And anything else that comes to mind.

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perhaps the idea that that dc supplies cause corrosion is an issue that has hung around from the days of flat ribbon feeder. a bigger issue imho is that few mast amps seem to have any voltage regulation. there is no regulation in the power supplies mentioned either, so ac or dc mast amp reliability has relied on the stability of the mains voltage! practically hasn't been a problem, but any spikes etc. are passed to the amp.

laceys.tv has had an interesting solution for the last year or so, tiny switchmode dc supplies. over a wide input voltage range they give no more or less than the required dc voltage and many spike incidents are smoothed. being smaller they look better, but they have some points of difference in their injectors too with even a couple of unique male to female f connector versions. these can be seen on pages 42 (43) of the flipping book catalogue at http://online.laceys.tv/pages/catalogue

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Corrosion can only be produced using DC, this is how electroplating works. Metal is removed and placed on another surface in the presence of a liquid.

So corrosion can occur with DC when it rains.

Corrosion is not possible with AC because the action reverses 100 times a second.

The reason for the move to DC is that the use of coaxial cable means that the inner conductor is better sealed against sun and water. The sun because it breaks down the plastic but not the shield.

The other advantage of DC is that the smoothing capacitor in the power supply is on the ground. In the AC case it is in the amplifier exposed to the heat of summer. This eventually dries out the capacitor (a component which costs around $1. The cost to replace it in labour is considerable.

Laceys trying to advertise their products again. The power required for a masthead amplifier is very small so a linear power supply is in expensive and cannot produce spikes. Switchmode power supplies chop up the DC to reduce the voltage from around 325 V DC down to the output voltage. Injectors with F connectors are commonly available.

Alanh

Edited by alanh
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Guest Malich

Corrosion can only be produced using DC, this is how electroplating works. Metal is removed and placed on another surface in the presence of a liquid.

So corrosion can occur with DC when it rains.

Corrosion is not possible with AC because the action reverses 100 times a second.

(Emphasis mine.)

Well, that's just wrong. Electroplating is done with DC, yes, but AC is well known to cause & accelerate corrosion. Just ask anyone knowledgeable about corrosion protection in the underground cable, pipeline, or electricity distribution industries. Or just fill your favourite AC-powered masthead amp with water, power it up, and check back in 12 months time.

AC causes less electrolysis than DC, but certainly not none. And corrosion is not the same thing as electrolysis.

Yet another example of Alan speaking not only well beyond his knowledge, but directly out of his arse.

(edited to remove the suggested AC masthead test, lest Alan just argue that any corrosion that develops is because of the DC on the far side of the rectifier.)

Edited by Malich
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Corrosion can only be produced using DC, this is how electroplating works. Metal is removed and placed on another surface in the presence of a liquid.

So corrosion can occur with DC when it rains.

Corrosion is not possible with AC because the action reverses 100 times a second.

The reason for the move to DC is that the use of coaxial cable means that the inner conductor is better sealed against sun and water. The sun because it breaks down the plastic but not the shield.

The other advantage of DC is that the smoothing capacitor in the power supply is on the ground. In the AC case it is in the amplifier exposed to the heat of summer. This eventually dries out the capacitor (a component which costs around $1. The cost to replace it in labour is considerable.

Laceys trying to advertise their products again. The power required for a masthead amplifier is very small so a linear power supply is in expensive and cannot produce spikes. Switchmode power supplies chop up the DC to reduce the voltage from around 325 V DC down to the output voltage. Injectors with F connectors are commonly available.

Alanh

Alan,. how do you explain the many ac and dc powered amps i'v had to replace due to corrosion? possibly they were doing a philo gender trick!

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Corrosion is not possible with AC because the action reverses 100 times a second.

Hmm another statement from preperation H that doesn't bare out in real world experience..... there's nothing to see just move on..... or is it mind the gap!!!!

I too have seen plenty of corroded ac amplifiers over the year

That being said with f connectors the issue s somewhat moot as this tends to considerably reduce the issue.

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The reason for the move to DC is that the use of coaxial cable means that the inner conductor is better sealed against sun and water. The sun because it breaks down the plastic but not the shield.

Another broken English, bizarre mangled unsustainable alanh fact?

Metalic migration with AC certainly is a problem. I'm sure that techies reading this thread got quite a chuckle when they came across alanh's post.

How one person can have such flawed understanding across such a broad range of concepts really boggles the mind.

Edited by DrP
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Lets see, copper conductor and copper braid shield,or copper conductor and aluminium shield held inplace by a stainless steel or

steel saddle and clamp of doubtfull quality,and add in the odd steel screw and brass washer topping off with some ants, spiders or ladybirds, then adding in some moisture from rain and snow and the big one salt air, now whats that pesky voltage AC or DC ??

Tazzy

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Guest Malich

You mean "electrolysis"? Well, Alan specifically said "corrosion" several times, though he went on to talk about electrolysis. He obviously doesn't know the difference.

Alan was quite adamant that "Corrosion can only be produced using DC" and "Corrosion is not possible with AC", which is flat-out wrong. Apart from the usual chemical processes that cause 'corrosion' (e.g. oxidation) which are a given, AC is well known to accelerate the process (although the exact mechanisms are debated). Based on what Alan chose to state he is absolutely & without doubt completely wrong.

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There is a lot of DC from the sun running around peoples roof tops now, are they all doomed ?

Seriously where is all this 'electrolysis' from power supplies found and how does it manifest its self to show up to be able to say this

is not 'corrosion'? I must be missing something. Is it found in mainly commercial large multi outlet installations ?

Having mainly worked in the Domestic area of tv installations all I can say is I am only aware of what I thought was plain old garden variety ' corrosion' from many causes.

Was the dropping of the AC power supply voltages from 24v down to 22v, 17.5v and 15v an attempt to minimise 'electrolysis'or just technology improvements or cost cutting, and now 14v DC is cheaper so must be better ?

Going by previous posts all the AC powered Amplified tv systems that have been going for 30 years are all ticking time bombs and all the new DC powered ones are in the future are going to fail and will keep the Franchise guys in lots of work repairing them.

Cheers Tazzy

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