Motorola SBV5220 Squaling PSU

[ratdude747]

I scored a motorola SBV5220 cable/telephony modem for $2.50 today... and it squeals.

The noise is coming from the internal PSU, a 14V unit from delta.

unplugging the PSU from the rest of the system lessens but doesn't eliminate the noise, which leads me to believe it's secondary capacitor issue. However, the caps in the PSU are all name brand, the main a nichicon PW. The other three lytics in the PSU are another nichicon PW and two rubycon YXFs. The primary cap, FWIW, is a panny of some sort (glued down), but being a high pitched squeal, I'd think it to be a secondary issue.

Recap the PSU anyway?

PS- the other caps in the modem are all taicons, which I'm not sure if I'll replace yet...

[kc8adu]

Re: Motorola SBV5220 Squaling PSU

i would replace all the lytics.
think about how many hours it will have run by now.
and how tired all those caps are.

[everell]

Re: Motorola SBV5220 Squaling PSU

The last squealing power supply I worked on had bad switching transistors. They worked, but they sang to me. I replaced them and the squealing disappeared. Some of those Asian made transistors are very questionable.....

[ratdude747]

Re: Motorola SBV5220 Squaling PSU

The last squealing power supply I worked on had bad switching transistors. They worked, but they sang to me. I replaced them and the squealing disappeared. Some of those Asian made transistors are very questionable.....

Noted. I'll nab those and the lytics too once my pay comes on Wednesday.

Pretty old unit, copyright 2005... and to think it's replacing a much newer looking Arris unit from bleeping time warner... any idea if this will be able to do 20mbs (what the current plan is rated for)?

[stj]

Re: Motorola SBV5220 Squaling PSU

https://cdn.badcaps-static.com/pdfs/...0b3593f20b.pdf

[ratdude747]

Re: Motorola SBV5220 Squaling PSU

https://cdn.badcaps-static.com/pdfs/...0b3593f20b.pdf

Been there, saw that, made no mention of max speed (or any real specs for that matter).

[ratdude747]

Re: Motorola SBV5220 Squaling PSU

Did some research, It's either DOCSIS 2.0 or DOCSIS 3.0. 2.0 was released in 2001, 3.0 in 2006. The unit is copyright 2005, but usually the copyrights on PCBs themselves predate the unit.

Either way, it will probably work fine for what my parents are doing... once I get it fixed up, hopefully TWC will let me give them the new MAC adresses w/o a service call (which would be BULLSHIT).

[kaboom]

Re: Motorola SBV5220 Squaling PSU

If you have more than one upstream/downstream RF channel, "bonded," it's running in DOCSIS 3.

DOCSIS 2 tops out over 30 mbps, but on a per-node basis.

Unless the cable plant is "fiber deep," with nodes every block or two, DOCSIS 2 won't cut it.

[ratdude747]

Re: Motorola SBV5220 Squaling PSU

^true (I do know they switched modems when we upgraded from 10mbps) ... Now to figure out which this unit is...

edit- it's a 2.0. Damn. paperweight.

[stj]

Re: Motorola SBV5220 Squaling PSU

look for a motorola "frog" modem.
we used to have loads of them in europe before docsis routers got cheap.
they were supplied with a linksys router as a combo.

[kaboom]

Re: Motorola SBV5220 Squaling PSU

^true (I do know they switched modems when we upgraded from 10mbps) ... Now to figure out which this unit is...

edit- it's a 2.0. Damn. paperweight.

Depends on the bandplan and modulation capabilities of the CMTS.

You'll have a block of channels (up/down) that support the modulation used for DOCSIS 3, which are "reserved" for that by default.

There can also be a few channels, for backwards compatibility, still set to support the older modulation, which are there for the old stuff.

Now if there are many customers with DOCSIS 2 equipment on your particular node, and just a few channels to go around, and that's the only node for a few miles, you may notice slowness during peak hours. This is not strictly a DOCSIS 2 issue- simply too few channels supporting the modulation your modem happens to require.

If TWC pushes fiber deep, there should be plenty of nodes around; so even with limited DOCSIS 2 channels, the aggragate bandwidth available is much higher than an old school system, with maybe a node every few miles.

SECV has a fiber deep, hybrid system, with nodes every few blocks- DOCSIS 2 is no problem. Lousy "consumer grade" routers are more of a problem here.

To get a rough idea of how far they're pushing fiber, look for these "snowshoes" on the poles.

http://www.qualitycable.com/LL_FIBOPTSS_.htm

It will probably still work. Try 192.168.100.1 to it, after hooking it to the cable system.

You'll at least be able to see if it locked on to any available channels. You should be able to see this even if the MAC hasn't been whitelisted. The RF side has to work long before it goes "online."