onkyo integra T4700 tuner

[Mr. Studio S]

My tuner no longer recalls the station presets once it is turned off. Where and what color is the capacitor I need to replace? Anyone have a picture of it? I'm sure I can do it myself if someone tells me the one I need to replace. Also anyone know of a good place to buy one online? Thanks!!

 

[Binkman]

Greetings; This maybe a little more complex than you think. following refers to the T-4500 but makes reference to the 4700 memory. (btw are you allowing a long charge up time with the tuner on?)

Cited from:
http://www.fmtunerinfo.com/onkyo.html

Stephan points out a problem affecting some T-4500s: "A significant number of T-4650s (and thus also T-4500s) appear to be affected by more or less serious amnesia. This has been traced to the microprocessor not going to sleep quickly enough when the tuner is turned off. (That would be triggered by pulling the /HLD line low.) Instead it continues running for a while, discharging the goldcap. You may not notice this as long as the goldcap is still in good shape, but as it grows older and its resistance increases (aided by nice warm temps near the display), the voltage may drop too much for the µP which promptly forgets all of its memories. My own T-4650 shows semi-serious symptoms, it wants to be warmed up properly in order to save its memories, but then it'll keep them for weeks without problems. It appears the goldcap is being charged veeery slowly. Maybe more is involved here. The cause for the problem appears to be cost-cutting during the main PCB design. The more expensive T-4700/T-4670 (same µP board, but different main PCB) features an additional transistor for pulling /HLD low and seems to be much less frequently affected. The successor T-407/T-4850 adds a 100 ohm resistor in series with the goldcap and another 1k resistor to avoid shock discharging of a 1µ/50V electrolytic involved.

 

[Mr. Studio S]

Thanks!!! I've read that. How long does the tuner have to remain on? I don't use it hardly ever, b/c commercial radio is so poor here in the bay area. I find myself using XM most of the time. I've had it on for at least 7 hours one day with no effect at all. Funny, my Fisher tuner sees less use and it still recalls stations set back in the early 2K's.

 

[Binkman]

The more expensive T-4700/T-4670 (same µP board, but different main PCB) features an additional transistor for pulling /HLD low and seems to be much less frequently affected. The successor T-407/T-4850 adds a 100 ohm resistor in series with the goldcap and another 1k resistor to avoid shock discharging of a 1µ/50V electrolytic involved.

Maybe change that 1uf 50v cap and or find a 'goldcap' and try that. Note the tuner must be on and illuminated for the station memory to charge up.. leave it on idle just the tuner is on. Time I don't know. My tx-82 keeps memory for about a 5 days to a week unplugged after using it frequently.

 

[Mr. Studio S]

left it on for two days and it still won't hold stations. Not a big deal. If someone has a picture of what I need to replace, otherwise it will stay like this or some day go to a repair shop.