What is this? SLN-6435A Matching Transformer

[henryg]

Hello. I found this part and was wondering what it is and what it does, black box, 1" x 2" x 1", 2 male banana plugs on one end and 2 female banana jacks on the opposite end. Thanks. Henry

[Mike B]

It is an accessory for testing/tuning a Spectra (it probably has other uses as well). It isolates the radio drawer speaker leads from grounded test equipment. This transformer goes between the radio drawer and speaker, with any grounded test equipment leads to be connected on the speaker side of the transformer. It is used because the Spectra series will blow up the audio amplifier chip on the command board if you ground either speaker lead. So, if you connect a service monitor with a SINAD meter to a Spectra speaker lead, pop goes the chip, unless you have this transformer.

I think it is supposed to be an 8 ohm in to 8 ohm out audio isolation transformer.

BTW, Motorola used to want over $ 85 retail on this part (I have not checked the price recently).

[kc7gr]

It is an accessory for testing/tuning a Spectra (it probably has other uses as well). It isolates the radio drawer speaker leads from grounded test equipment. This transformer goes between the radio drawer and speaker, with any grounded test equipment leads to be connected on the speaker side of the transformer. It is used because the Spectra series will blow up the audio amplifier chip on the command board if you ground either speaker lead. So, if you connect a service monitor with a SINAD meter to a Spectra speaker lead, pop goes the chip, unless you have this transformer.

I think it is supposed to be an 8 ohm in to 8 ohm out audio isolation transformer.

BTW, Motorola used to want over $ 85 retail on this part (I have not checked the price recently).

They still do. I looked it up not that long ago.

Then I turned around and bought this unit from a fellow in Florida who specializes in military surplus electronics.



I've used it on Spectras and Maxtracs alike when doing SINAD measurements into a grounded input port. Works great!

[Will]

The Motorola transformer also helps remove the "thump" in the speaker when the radio audio amp is enabled and disabled. Got a love bridge audio amps!!!

[GEMOTO]

Would this product from Radio Shack be a suitable Replacement for connecting Spectra's etc. to grounded test equipment?

http://www.radioshack.com/product/index ... Id=2062214

The SLN6435 is NLA from Motorola.

[Al]

In looking at the website, they don't say what's inside the box. Could be transformers, but more likely just straight capacitor coupling from input to output on the common sides of the inputs and outputs. The Mouser Electronics 42TU016 transformer, 600CT/600 CT is what's used in the RLN4460C test box. You *know* you'd be safe if you used one of these.

[GEMOTO]

Thanks, Al.

I called Parts ID and the gentleman was very helpful. He confirmed that the SLN6435A has been discontinued.

He pulled up an internal drwing and gave me the part numbers from it. Thre is no number for the housing or bannana jacks but he gave me the following:

2584903H01 - Raw Transformer (600/600 OHM)

0400007683 - 2 Lock Washers

0300008022 - 2 Machine Screws

[Al]

2584903H01, according to Accesspoint is available for $42 and change. 42TU016 in single unit from Mouser is $2.16. If you're going to use it for SINAD measurement only, should not make any difference which one you choose.

[GEMOTO]

I got the one from Mouser